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Tales From the Dark Side: Putting Car Tires on Motorcycles

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Eric Trow
June 11, 2012
Filed under Features, Motorcycle Tires: Reviews

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Have you ever found yourself unwittingly in the middle of a heated religious or political debate between two vehemently opposed participants? Not since the dispute over conventional oil vs. synthetic oil have I seen such polarized and passionate opinions in the motorcycle world. The question is, unlike the face off over the slippery stuff, could this practice by those known as “Dark Siders” actually be a dangerous one?

“I’m interested in signing up for one of your Stayin’ Safe training tours,” the email began. “But before I register, I want to make sure it’s OK to participate if I have a car tire mounted on my Gold Wing.” A what? Did he say a “car tire?” I have to admit I had never heard of such a thing. Nor could I fathom why anyone would want to do it. As difficult as it is for me to turn any rider away who is interested in improving his or her skills, my response was, “I’m afraid we have to say no.” I was concerned about the potential risk for this rider and others on the tour—especially knowing our tour would include some tight and technical mountain back roads with switchbacks. My decision to turn this rider away (along with a handful of his riding buddies) was based on my belief that riding with a car tire on a motorcycle could not possibly be a good idea or a safe practice. But I had to admit—and I did to this gentleman—my knowledge of the practice was extremely limited. I would need to learn more. As it turns out, that would require a trip to the Dark Side.

Behold, the Dark Side: A growing sect of riders that promotes the use of car tires on motorcycles

Dark Siders (they call themselves that) are part of one of the most evangelical groups of motorcyclists I’ve encountered. They are deeply passionate about their practice of using car tires in place of prescribed motorcycle tires on their bikes. And they are more than anxious to profess those beliefs in the hope others might also see the light. Or the dark, as it were. It borders on a religious movement. Needless to say, it was not difficult to get their side of the story. In fact, after I broke the news to the prospective student, I was soon flooded with emails from other Dark Siders, each enthusiastically sharing his personal testimony, telling of his conversion to a life of riding on the dark side, never to return to conventional practices again. “Remember, the earth was once flat too,” one Dark Sider offered.

Another went further to explain the extent of their mission, “Being that we are free thinkers, we push the envelope all the time trying new, different, bigger, winter, summer, truck tires on our various scoots.” These riders believe, rightly or wrongly, that car tires provide more economy and are less likely to fail than motorcycle tires. Some even believe them to be safer. Others were quick to accuse tire companies, claiming they know how to make motorcycle tires that last longer and cost less but, instead, scheme to make as much money on riders as they can.

Personally, I view motorcycle tires as high-performance tires and expect that to come at a price. When compared to their high-performance brethren from the automotive world, I have found motorcycle tires to be on par when it comes to performance, cost and wear characteristics.

Although it has spread to other makes and models, this movement appears to have originated among a number of luxury-touring motorcycle riders who claim to have experienced repeated motorcycle tire failures on these behemoth machines. Issues reportedly extended from very rapid tire wear to poor handling to blowouts and tire delamination (potential causes and preventive measures for these issues can be found in the accompanying story). So, some riders turned to car tires as a fix. And, once they found a shop willing to mount the car rubber on a bike rim, they began to accumulate miles without serious consequences (although most admit to the bike handling “differently”). The practice of mounting car tires to the rear of motorcycles began to expand and the order of Dark Siders grew as other riders were attracted by economics. Car tires, at least the ones they were choosing to fit to their bikes, tend to be less expensive and reportedly provide longer tread life. Predictably, some riders even began to mount car tires on the front rim, as well, and others have followed.

Dark Siders claim to have collectively ridden millions of miles on car tires without a reported crash resulting specifically from car tire failure (although there is no clear way of knowing if tire handling issues have played a contributing role in any crashes). One Dark Sider proudly claims that on one forum alone there are more than 1,000 touring bike owners who swear by them. Realistically, there have also been millions of incident-free miles covered by helmetless or poorly dressed riders, but I’m not ready to leave my gear at home simply because others have been able to do so without landing in the hospital or morgue.

Two BMWs. Both executing the same curve. Each with distinctly different handling characteristics and demands on tires.

Two BMWs. Both executing the same curve. Each with distinctly different handling characteristics and demands on tires.

Admittedly, I appreciate people who think differently. It is unconventional thinking that has led to some of the most significant inventions and greatest advancements in human history. Unfortunately, not all alternative ideas are good ones. In fact, most aren’t. The time I tried to use my walk-behind lawnmower as a snow thrower during one particularly bad winter comes to mind. It is true that necessity (or was it desperation?) often is the mother of invention. Just for the record, despite my own freethinking and stubborn determination, a lawnmower makes a horrible snow thrower. Even after you remember to remove the bagger. The point is, experimentation—especially when conducted outside of a testing facility and beyond the collaboration of industry experts—can have a dark side of its own.

Shedding light on the Dark Side argument: The industry’s view on the role of the motorcycle tire

In search of a balanced argument, I reached out to motorcycle manufacturers, tire manufacturers, heralded motorcycle safety experts and industry leaders to get their take on the subject. Not all are quoted here, but their input for this story was consistent.

Before we delve into any comparisons to car tires, let’s first look at motorcycle-specific tires themselves and the role they play. One of the first things that the motorcycle manufacturer points to is the tire as a vital consideration in the overall design of a motorcycle. Tire choice is never an afterthought for the manufacturer. Quite frankly, it can’t be. Nathan Boyd, P.E., Director, Product Integrity at Harley-Davidson explains, “We look at the motorcycle as a complete system where the tires, the wheels, the swingarm, the forks and the frame are designed to perform together. Changing even one of those components can alter the bike’s intended characteristics.” So naturally, tire specifications are developed for each machine and then tested extensively to assure the optimum performance the product development team was looking for is achieved. Any deviation from that formula would potentially influence handling and safety. With so much thought, analysis and evaluation put into making sure that tires work as part of the bike’s overall system, it’s easier to understand why the factories urge riders to stick with what has been proven to work by highly skilled engineers, researchers and testers. Boyd punctuates that point. “As a motorcycle manufacturer, we feel strongly that use of tires outside our specifications is inappropriate, including using automobile tires on motorcycles.” Like all manufacturers, Honda has developed clear tire guidelines and specifies approved tires for its motorcycles, including the Gold Wing, and recommends that owners refer to their owner’s manual when making tire choices.

Two BMWs. Both executing the same curve. Each with distinctly different handling characteristics and demands on tires.

Two BMWs. Both executing the same curve. Each with distinctly different handling characteristics and demands on tires.

Even among motorcycle-specific tires, there can be tradeoffs when fitting non-specified tires to certain bikes. Imagine the potential compromises associated with installing a tire that was never intended to function on a motorcycle in the first place.

A one-track mind: The differences between car and motorcycle tires

According to Mike Manning, Dunlop Motorcycle Product & Marketing Manager, “There are several considerations when looking at tire design and use for a single-track ‘camber’ vehicle such as a motorcycle vs. a 2-track vehicle like a car or truck. Tire profile, construction and compounds are developed specifically for each type of vehicle.” Why? Because cars and motorcycles handle differently. A lot differently. Take a look at the images of the sports car and the bike negotiating the same sharp left-hand bend. Although both are BMWs, their handling—and the demands on their tires—are remarkably unalike. The bike leans into the bend, rolling onto the inside edge of its tires. The car remains relatively flat or leans out of the curve, placing the vehicle’s weight on the outer edge of the outside tires. Is there any wonder why the tires for each are designed differently to handle the unique forces placed upon them?

As the Motorcycle Industry Council puts it in its Tire Guide (developed in cooperation with the Motorcycle Safety Foundation and the major tire and motorcycle manufacturers), “Because a motorcycle is a single-track vehicle and leans as it turns, motorcycle tires are quite different than car tires. Whereas car tires have a fairly flat profile and a contact patch that varies little in size or shape, motorcycle tires have a U-shaped profile and a contact patch that changes size and shape during cornering.” The shape of a motorcycle tire is designed to maintain a consistent contact patch throughout lean. A car tire in this application would be flat and fat when upright and thin and narrow when leaned. “Car tires and motorcycle tires are constructed and designed differently due to the different ways in which they are used,” warns John Mosby of Kumho tires, one of the auto tire brands often selected by Dark Siders. “Kumho passenger car tires are not made to absorb the reduced contact patch at high camber angles that motorcycle tires frequently experience. Because of this, durability can be affected by operating at such high camber angles, which can lead to tire failure. We strongly discourage anyone from using Kumho passenger car tires on their motorcycle.”

The profile of a motorcycle tire clearly has one large-diameter ring in the middle that tapers to smaller rings at each side (creating the U-shape). As the bike leans, this makes rounding curves much easier than if the tires were square like those of a car. Here’s a quick demonstration. Grab an empty soup can from the recycling bin and a tapered coffee cup (that empty caramel macchiato cup will do nicely). Lay each on its side and roll them across the table. The can, shaped like a car tire, will track straight. But the tapered coffee cup, because it has larger and smaller diameters much like one side of a motorcycle tire, will want to turn. As you lean your bike from the large ring in the center toward the smaller ring on either edge, you are also in effect reducing the gearing of your bike, thereby slowing it in a curve. That makes it easier to add throttle through the bend as prescribed by most riding proficiency experts, which in turn stabilizes the bike’s chassis for smooth cornering. The square car tire does not provide that advantage when leaned.

Beyond tire profile, sidewall stiffness plays an important role in motorcycle tires. The sidewall acts as a suspension component and must also provide enough rigidity to not only stand up to the unique forces placed upon it during cornering, but to also take advantage of those forces for precise handling. According to Dunlop, “When the bike is vertical, the bike’s suspension system does much of the work in keeping the tire in contact with the ground and controlling the ride. When the bike is leaned, there is less mechanical suspension and more tire suspension characteristics at play. The bike tires are designed and constructed specifically for this use.”

Motorcycle tires are uniquely designed to maximize the contact patch for greater grip at all lean angles.

Motorcycle tires are uniquely designed to maximize the contact patch for greater grip at all lean angles.

Most modern motorcycle tires use multiple rubber compounds; harder compounds in the center to maximize tread life for highway riding and softer compounds toward the edges to maximize grip when the bike is leaned. Car tires have just one compound since they are not designed to be leaned over or to contend with camber forces.

While use of a car tire might have no severe consequences during normal riding, it could be problematic when performance really counts, such as when a threat unexpectedly appears directly in the path of the rider. The bike fitted with a car tire cannot be relied upon to respond as well as one with a motorcycle-specific tire when maximum traction and precise handling are needed. Is it ever acceptable to give up even a small degree of performance advantage when that small compromise could be enough to make an avoidable crash an unavoidable one? Stayin’ Safe founder Larry Grodsky once had a rider ask him if he really needed to wear protective gear. “No,” Larry replied. “Just wear it on the day you crash.” I suppose the same could be said for tires. Just use the motorcycle tires on the days when you need to avoid a crash.

The bottom line? The manufacturers, engineers and safety experts I spoke with all said the same thing; riders need to realize that this is not a good idea. The Motorcycle Industry Council puts it more directly, “Never mount a passenger car tire on a motorcycle rim; the flat profile of a car tire is incompatible with the dynamics of a vehicle that leans as it corners, and the section of the tire in contact with the rim (the ‘bead’) is incompatible with motorcycle rims.” A motorcycle calls for a tire that was developed to be a specialist in single-track vehicle dynamics. Dare I suggest that it’s not unlike the way brain surgery calls for a specialist in neurology. Would you turn to a gastroenterologist for that procedure because he or she has a lower hourly rate than a neurosurgeon? Both may be experts, outstanding in their respective fields, but neither would be a wise choice to fill the other’s role. As motorcyclists, we have need for a specialist: the one that was developed specifically for the demands of motorcycling.

The darker side of the Dark Side argument

Still not convinced? Even if you believe that running a car tire on your motorcycle fits within your acceptable risk threshold on the road, you may have left out an important consideration that can strike a little closer to home. Can the rider with a car tire mounted on his motorcycle have complete confidence that, in the event of a crash, he will be covered by his insurance? Or that others injured in a crash won’t target him with a costly lawsuit because he fit his motorcycle with tires that were not designed or intended for motorcycle use and may have contributed to the crash? Are the few dollars saved by turning to a car tire outweighed by the potential loss of a house and whatever dollars may be squirreled away for retirement?

As motorcycle safety expert and AMA hall-of-famer David Hough said during our recent conversation on this topic, “Motorcycle engineers get up awfully early in the morning to calculate what works best for bikes. An owner who disregards the engineers’ advice should think carefully about his or her talents in being more clever than the engineers. The owner who installs tires not designed for the task must take full responsibility for the results.” While the practice of fitting a car tire to a motorcycle may work suitably for some—even over many miles—there is no escaping that the rider must accept full liability for a practice that is not endorsed by the industry. Riders must consider carefully what accountability they may have as they openly encourage other riders to adopt a practice that is ardently discouraged by virtually all experts in the industry, including those who have no financial gains in selling more motorcycle tires.

Being a safety-oriented rider and writer, I’m inclined to make decisions that will limit my exposure to potential danger and to personal liability. While I am a huge proponent of creative and unconventional thinking, I am opposed to casual experimentation when life is on the line. Although I am tempted to trust the word of the many riders who have been able to clock thousands of miles on car tires, I place more trust in the collection of specialists working together on a daily basis to make sure that all components of a motorcycle work in harmony—not just to create a better rider experience, but also to avoid lawsuits due to product failures. So, upon careful investigation and consideration, my answer to the gentleman who inquired about taking our Stayin’ Safe on-road course with a car tire mounted to his bike would still be the same. Only now, I feel that I have done the due diligence to understand why.

(This article was published in the July 2012 issue of Rider magazine.)

Related:
Avoiding Tire Failure: http://www.ridermagazine.com/browse-by-type/tires/avoiding-tire-failure-getting-the-most-from-the-tires-that-were-meant-for-your-bike.htm

Erasing Doubt: http://www.ridermagazine.com/browse-by-type/tires/erasing-doubt-car-tires-on-motorcycles.htm

Letters to the Editor: http://www.ridermagazine.com/latest-news/letters-to-the-editor-dark-side.htm

Comments

114 Responses to “Tales From the Dark Side: Putting Car Tires on Motorcycles”

  1. Erasing Doubt: Car Tires on Motorcycles | Rider Magazine on June 11th, 2012 2:25 pm

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    [...] tire pressure drops below 25 psi. Related Content Last 5 stories in Motorcycle Tires: ReviewsTales From the Dark Side: Putting Car Tires on Motorcycles – June 11, 2012Erasing Doubt: Car Tires on Motorcycles – June 11, 2012Dunlop Sportmax Roadsmart II [...]

  3. Donald Smith on June 11th, 2012 10:40 pm

    (Although it has spread to other makes and models, this movement appears to have originated among a number of luxury-touring motorcycle riders)
    Sorry Eric, but you are wrong about where this all started. While I don’t endorse the practice I do know it’s been going on since at least the 50′s, (probably earlier) with Bobbers & Choppers. Speeds in rural areas averaged more towards the 45 mph range due to road conditions, and the bikes involved. A 45 ci Harley wasn’t very fast, and 50 miles was a hard days riding here in West Virginia. My Dad didn’t use car tires (He was too fast to trust them), but a multitude of his ridding buddies did. In the 60′s I had a bike with a 15″ rear wheel, and tried it too. Seemed to do OK to me at the time, but most of my riding was on gravel, and woodland trails. A skinny V W mud & snow tire, and I never got stuck in the mud.
    That was then. Now most bikes have no trouble doing the ton, and beyond. Even my old 650 Yamaha will do 110. Car tires? not anymore, but there was a time back in the good old days when motorcycling was fun & inexpensive.

    [Reply]

  4. DaveA on June 12th, 2012 10:08 am

    In the words of vehicle dynamics expert Chris Rock…

    “Yeah, you can do it…but it don’t mean it’s to be done! Sh@t! You can drive a car with your feet if you want to; it don’t mean its a good f*%kin’ idea!”

    [Reply]

  5. Sean Alexander on June 12th, 2012 12:42 pm

    If dynamic limitations dominate the safety side of the car tire vs. bike tire argument, then a follow-up article should be done pitting a typical cruiser fitted with fresh motorcycle tires against a typical sport-standard fitted with an average sportscar tire if the appropriate width. Am I not correct in assuming that a modern sporting “standard” would still possess vastly superior dynamic performance, even when fitted with a sportscar tire? If so, then (in the absence of any evidence pointing to higher failure/pressure loss rates for car tires in motorcycle applications), the best advice from a safety standpoint would have to be first, not to ride cruisers, and then second, not to ride on car tires. Or am I missing something?

    [Reply]

    Vlad Reply:

    You are missing one other point. If motorcycle manufacturers are so carefully matching their products with adequate tires, how come virtually every customer replaces the universally crappy OEM rubber with vastly superior aftermarket motorcycle tires that better suit their riding style and their motorcycle? Why only those that don’t know better buy only OEM oil and filters?

    Let’s face it – all manufacturers will fit the cheapest OEM tires they can get away with, just like they’ll charge you a premium for generic oil with their logo on it. Sure, the bikes may be designed for and/or tested with said tires and oil but that doesn’t mean those products are best for them. At most, they are a (relatively) safe bet for those that don’t know better. Anyone who says different needs to get their head out of …

    [Reply]

  6. Dave on June 13th, 2012 4:34 am

    I’ve been riding with a car tire for over 2 years with over 15,000 miles, rode twisties from Arkansas to West Virginia. I have worked in manufacturing for 25 years. One thing I’ve learned is that there are alot of technical, scientific or safety related reasons something should not work but you try it and it just does, I’d like to see instead of you telling us it should not work, do some actual riding/testing and prove it will not work.

    [Reply]

    Don Reply:

    Dave, I have been riding the darkside on my Yamaha Roadstar for the last 19,000 miles and love it. I think there is too much on why it shouldn’t work either. Hell, when I was in the Navy, I worked on Helicopters, and according to “Theory” they aren’t supposed to be able to fly either. Scientifically, they should never leave the ground…. but don’t tell Bell or Sikorsky that.

    I know I can ride 90 safely with mine. I have a higher load rating for riding 2 up with full saddlebags and luggage on the pack. I have better stopping power and that makes me feel good on wet or snow covered roads (I ride all winter in Wisconsin too).

    BTW, I only run a CT on the rear of the bike, and to start another argument, I run a MC rear tire mounted in reverse on the front… also adds more stopping power.

    [Reply]

    BBunsen Reply:

    “I worked on Helicopters, and according to “Theory” they aren’t supposed to be able to fly either.”

    That’s not true. There are established aerodynamic principles that explain exactly why helicopters are able to fly. In fact, every helicopter designer and manufacturer has used those principles to build their machines.

    [Reply]

  7. Frank LeClair on June 13th, 2012 12:03 pm

    There’s one glaring inaccuracy in the article:
    “Predictably, some riders even began to mount car tires on the front rim, as well, and others have followed.”

    That’s simply not true. I am not aware of anyone who has mounted a car tire to the front wheel of their motorcycle. If you’re referring to those who do what is known as “Double Darksiding,” that is the practice of mounting a rear motorcycle tire to the front of a bike, not a car tire.

    The article seems to be a lot of talk and absolutely no action, intended to bolster only one side of the argument – The author’s belief that car tires on the rear of a motorcycle are a bad idea. Instead of writing the article from a desk, how about Rider magazine does some real-world and/or track performance testing to see how a car tire really stacks up to a motorcycle tire? Do the testing that all the manufacturers refuse to do?

    Tire and motorcycle manufacturers claim a car tire simply can’t work as well as a motorcycle tire because it wasn’t designed for the task. Riders who actually TRY it claim differently. There’s only one way to resolve it: Test identical bikes with car and motorcycle tires in braking, swerving, and handling tests! Test tire hardness and traction ability between MC and Car tires (did you know car tires are SOFTER?) and measure the actual shape and size of the contact patch on a car tire when used on a motorcycle.

    I’m not disregarding what the engineers know. The article is correct, they’ve worked hard to ensure the whole motorcycle works as a whole, and designed tires to work well for that task. However, just because something isn’t designed for the specific purpose doesn’t mean it can’t handle the task just as well, if not better in some respects.

    After the first rear Metzler ME880 Marathon motorcycle tire on my Kawasaki Vulcan 2000 only lasted 4500 miles before wearing out (flat in the middle), I researched carefully and decided to try a car tire (General Altimax HP) on my motorcycle two years ago, which I have ridden with for almost 8000 miles now. From my research and personal experience, I’ve understood that car tires are designed to take much more weight and much more strenuous forces on a car than they ever experience on a motorcycle. They provide better traction because of their softer rubber compound than a motorcycle tire. While the contact patch gets narrower when the bike is leaned than when the bike is going in a straight line, the sidewall “flexes” to keep a large contact patch on the ground when the bike is leaned over – the contact patch gets longer as it gets narrower, the tire never rides up on the edge or sidewall. I’ve already put almost twice the mileage on this car tire as I got out of the previous motorcycle tire, and have pushed the performance of this tire much harder than I ever did the MC tire. I have yet to be disappointed or find anything it can’t handle.

    I challenge Rider magazine to do some thorough investigation of the issue instead of allowing bias to determine the result.

    Frank LeClair
    Springfield, OR

    [Reply]

    Bruce Dimon Reply:

    ” While the contact patch gets narrower when the bike is leaned than when the bike is going in a straight line, the sidewall “flexes” to keep a large contact patch on the ground when the bike is leaned over – the contact patch gets longer as it gets narrower, the tire never rides up on the edge or sidewall.”

    A friend told me the same thing. I followed his Gold Wing with a car tire across West Virginia and observed the opposite. The side wall did not flex enough to keep the tread on the pavement. In every corner it rode up on the edge so that only a narrow strip of rubber was on the road. The more he leaned, the less rubber was on the road. At a stop you could see how the tread was rounded on the edges. This tread was not designed to be the only point of traction in a curve and was designed to act against cornering forces from the opposite direction.

    He kept the pressure low enough that I could see the tire deforming over bumps. This added a weave when the bump was in a corner. In spite of this, he claimed it held a steady line. After what I saw, I would never try a car tire on a bike.

    [Reply]

  8. Art Lewis on June 13th, 2012 4:01 pm

    Well, with 10,000 miles on my 14 inch Bridgestone on the rear of my 09 650 Burgman, I can report no problems, very little wear, and I suspect at
    least 25-30,000 more miles of use. My daily riding is 44 miles mixed secondary and freeway. Darksiding seems to be a bit more popular with us scooter riders. Some have reported as many as 100,000 miles of “darksiding” on their scooters with no issues to speak of.
    If I were sport riding and touring, I would have stayed with the recommended scooter tire.

    [Reply]

    dan davis Reply:

    what size & brand of tire do you have on the rear ? & do you know a larger cycle size tire to put on the front ? For a Burman 650
    THANK YOU, Dan Davis

    [Reply]

    Art Lewis Reply:

    Dan, I’m riding a Bridgestone Potenza 165/65 R14 on the 09 Bergy 650.
    I have not changed the front from OEM recommendations, although I am on my second front tire. I have not seen anything on Bergman usa website about changing the front tires to an auto type. There may even be some clearance issues in the front as well..not sure.

    [Reply]

  9. Macgyver on June 13th, 2012 5:26 pm

    I’m a member of the luxury touring bike forum you spoke of in your story. (I call it a story as it produces no real world technical data to prove the claims of car tire use as a safety issue.)

    I am also a double darksiders , as I run a Bridgestone BT-45 battalax rear tire on the front wheel and a Michelin Primacy Alpin PA3 ZP. (run flat) on the rear wheel. I’ve always until now ran motorcycle tires on motorcycles . after long searches on each motorcycle I’ve had ,I finally found a tire combination for each bike that balanced tread wear and traction to achieve the best of both.

    The Goldwing is a completely different animal in those regards, it eats tires for lunch under normal riding conditions and when rode hard in twisties tires don’t last any time at all.

    So, I challenge you and the motorcycle tire manufactures to come up with a motorcycle tire that will give us long tread life, traction and the safety of a MT that you so claim at a reasonable cost.

    I also challenge you to take a ride on a Wing with a car tire mounted on it and give a real review of that experience , instead of the typical propaganda the tire manufactures are stuffing down your throat because they are paying your bills.

    [Reply]

  10. Thomkat on June 13th, 2012 6:52 pm

    While I agree with Eric’s reasoning on not using a car tire on a two wheeled motorcycle, those arguments don’t seem to hold for trikes. A trike doesn’t lean and the tires are subject to similar forces a car puts on it’s tires, so why not?

    [Reply]

    Jim Giles Reply:

    I have never seen a trike with anything but auto tires on the rear has anyone else?

    [Reply]

  11. Rob on June 14th, 2012 5:08 am

    I agree with Frank…I think Rider magazine should do some testing on a GL1800 Goldwing with both a car tire and a motorcycle tire. Put it through the paces and even try them both at the track where the tires will REALLY be put to the test! Reading an article like this from someone that has not even TRIED what they are writing about is basically an insult to people that have logged hundreds of thousands of miles on car tires.
    Eric Trow is just another naysayer about car tires just like a lot of others were until they actually TRY running a car tire and really do some REAL WORLD testing with them and make an INFORMED decision on their use.
    Honestly it is beyond me why this article was allowed to be printed on heresay. I myself am now running a Pirelli run flat on my Goldwing and am loving it!!! The day that those experts on motorcycle tires make a RUN FLAT motorcycle tire…that will be the day a lot of darksiders might think about going back….or maybe not.

    [Reply]

    seventhson Reply:

    And if they do a test and you don’t like the results…. will you then find another complaint about that article….there is no pleasing you people….other than to whole heartedly agree with you on this polarized subject.

    [Reply]

    Rob Reply:

    No I just wish that people make an INFORMED decision and comment on a subject they actually experienced for themselves before passing judgement on how unsafe something is. I have no problem with someone trying a car tire and then deciding it is not for them…where I do have the problem is people with the doom and gloom attitude on something they know nothing about!

    When you say YOU PEOPLE…obviously you have not experienced it either. If you don’t…that’s ok. I know how it is and the safety of a run flat not to mention the higher load bearing tire. I am happy with my decision to run my car tire.

    If they test the tires and compare them to the hottest motorcycle tires I can bet they will be very surprised.

    [Reply]

    Frank LeClair Reply:

    Actually, Seventhson appears to be one of the very few people who tried a car tire on his machine (Yamaha Stratoliner) and didn’t like it. Had some stability issues (a wobble at higher speeds) as well as didn’t care for the way the car tire “wallows” in highway ruts, or other road surface irregularities.

    I’ve had my car tire on my Vulcan 2000 for about 8000 miles now without any complaints. The way it handles uneven surfaces like highway ruts or pavement seams is a minor inconvenience compared to the other advantages like increased traction, much longer tire life, and smoother ride. Solid as a rock at high speed, (even stable at 70mph on gravel!)

    Rob Reply:

    I currently run the Pirelli Eufori 195/55 R16 on my wing. I have about 6500 miles on it so far and not one instance of instability or problems with cornering. It does tend to follow groves in the road at low speeds like coming up to a stop light at times but overall has been a great tire. My next tire will be the Michelin Primacy Aplin which has been dubbed the closest to a MT.

    The thing that sticks in my side are the ones that say you will crash and burn running a CT and have never tried it for themselves. I would love to hear if anyone can remember any car tire delaminating…I can tell you of MANY MT’s that have done so and the flat spot that forms on MT’s give them a weird feeling when cornering.

    Sean Reply:

    Consulting engineers from both motorcycle and automobile tire manufacturers is in fact making an INFORMED decision. The automobile tire manufacturers clearly state their tires are not designed for motorcycle use.

    Derek Reply:

    Sean,

    The Hitachi Magic Wand was also not designed for what your girlfriend uses it for but if it gets the job done better than you do shouldn’t she use it?

    Bread was not designed to hold slices of meat, I don’t see anyone complaining about sandwiches today.

    I could pick so many things apart about this article it’s not even funny. Perhaps I will do a detailed breakdown of this article later and point out the many flaws, misinformation, out right lies and how about every other sentence is worded in a manner that drips with disdain towards those who choose to run a CT.

    You can tell that this writer never checked into darksiding for the intent of giving it an unbiased chance. He had his mind set before he ever started researching. His ungrounded hatred toward it seaps out in almost every sentence.

    This article is great for one thing. Showing who the real zealots and religious nuts are.

  12. Vern Neal on June 14th, 2012 7:51 am

    I too spoke out against the use of a car tire on a motorcycle. The article is skewed in that they asked Dunlop Motorcycle Manufacturers what they thought. Of course they would be one sided. The facts are I put a Michelin Alpin PA3 Car Tire on the rear of my 2010 Goldwing with a Bridgestone B709 MT on the front. Why to prove the Darksiders wrong. Three months latter and I have proved myself wrong. The tire has a more round profile very simular to the Dunlop D250 MT. The Michelin stops better, takes curves BETTER than my old MT, has a larger contact patch, is a runflat and can be run with no air, is safer in the event of an air leak, is smoother and does not cup. This article is total crap as is the magazine.

    [Reply]

  13. phil jones on June 14th, 2012 11:42 am

    This article has not been technically researched, in my opinion. the people referenced were not engineers or manufacturing types but were marketing and company representatives. So we have a ‘journalist’ spewing opinions from others …who have opinions. We also have people who are stating facts that they have done it and the results of doing it. your magazine is becoming less creditable.

    [Reply]

  14. Rodney106 on June 14th, 2012 8:07 pm

    The problem with your theory is that certain car tires actually work very well on big touring bikes like the Gold Wing or Electra Glide. They work so well that you can take them to a track day and fly around corners raising sparks. Check YouTube and see for yourself.

    [Reply]

  15. Darkside/downside on June 14th, 2012 8:25 pm

    [...] Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine here is the link. gotta say though the bit where the guy from harley says every tyre is designed for the bikes characteristics makes me laugh i agree to a point but it is funny how u can walk into say a triumph dealership and everybike in there has metzelers on it lol i dont think they took the characteristics into consideration at all they just put on whatever metz fits the rim as they are the supplier of their tyres im still not ever trying one but i keep an opened mind also [...]

  16. Michael on June 15th, 2012 4:14 am

    Dunlop seriously needs to go back to making car tires, we call them DUNFLOPS for a reason! They make tires for the manufacturers of the motorcycles so they have a contract. The quality is subpar, the handling is terrible and the amount of mileage I get is about 4500. I agree with the other readers here you should do some testing! You should at the minimum ask someone other than DUNFLOP mfg. The worst MC tire ever made!

    [Reply]

  17. Bobby Bee on June 15th, 2012 9:56 pm

    If you can afford a Goldwing, tires should not be a problem for you.

    [Reply]

  18. Todd Griffis on June 16th, 2012 1:32 pm

    I read this article with much enthusiasm because I have a co-worker that runs a car tire on the back of his highly modified Triumph Rocket III. He swears by it, mainly because he’s pushing well over 200 hp at the wheel. Everything he has said about running the car tire seems to fit right in with what the article states. Very interesting stuff!

    [Reply]

  19. Douglas Engstrom on June 16th, 2012 8:27 pm

    In regards to insurance coverage, if my Triumph and BMW call for Metzlers and I use Dunlops of the same size and ratings because of cost and possible mileage gains, am I also screwed in the event of an accident? I switched to a car tire rear on my Rocket 111 and after a short learning curve am quite happy with it. It does handle differently because it is quite wide but two up it is just as flickable as with the old Metz, which was fubar at 6000 miles. I have 10,000 on the CT with no discernable wear or problems…and it cost a hundo mounted.

    [Reply]

  20. Too Tall on June 16th, 2012 11:17 pm

    Since when does Rider magazine write articles for the sole purpose of mocking a large group of riders because of their equipment preference. The author was intent on insulting this group rather than providing any actual test data or trying to understand why car tires on motorcycles has become so popular.

    The author says he has never tried a car tire, so how would he be qualified to make a judgement. He’s not. This was simply an article about his opinion, not fact.

    As a result, this is one long time subscriber who will not renew. Roadrunner is a far superior magazine with great touring articles and downloadable GPS tracks.

    [Reply]

  21. Tony Verrette on June 17th, 2012 3:14 am

    Agreed, complete opinion piece. I did over a year of research prior to going to the Dark side. On my cruiser, I will never buy a MC tire again, at least not until the tire prices come down and the longevity comes up, and maybe not even then, as they simply don’t have the contact patch of a CT. Hey, check this out, too- There are still many MC tire blowouts, delaminations, and general tire failures. Can any of you remember the last time you had a car tire fail you from manufacturing defects? I do recall Firestone had a bad go with some tires Ford was using in the early ’90′s, but that’s about it. The overwhelming majority of car tire failures are from road hazards, potholes, nails, screws, gashes from debris on the road, or significant others potentially tearing them open with a kitchen knife! They also fail occasionally due to dry rot. When’s the last time you saw a MC tire with dry rot? Never, if it’s ridden with any frequency. Why? Their tread surface wears out long before the rubber compounds begin to deteriorate.

    I can also tell you that his tin can/styrofoam cup “test” is invalid. Simply go on Youtube and search for video of darksiding motorcycles. You will see, even in full peg-dragging cornering, there’s still almost 50% of the tread surface contacting the road!

    Sorry, I won’t believe a story written by someone who did no actual research, has not experienced it, and relied only upon those who stand to lose money or business by endorsing this. I have contacted my insurance, and been informed that if the tire is DOT legal, there is no problem with coverage.

    Eric Trow, stop the fear-mongering! I don’t tell anyone they should go to the dark side. However, if you are considering it, there are a ton of resources out there for your education. Utilize that prior to making your decision. Don’t base that decision on an ill-informed opinion-filled story.

    Tony
    San Antonio, TX

    [Reply]

  22. Len Reddie on June 19th, 2012 1:32 am

    There is an issue that the article failed to address, and that is “load factors”. With these ‘behemoths’ weighing in at heavy, plus a full-size rider and their full-size SO as a passenger, there is no weight left over to fill the tank without overloading the MC tyre!

    If the manufacturers are designing their machines from the tyres up, then they should make sure the tires that they are selecting are able to carry the loads that their machines are required to carry.

    I looked at this article hoping that it would provide balance, and found it full of opinions, hear-say, and advertising-speak that does nothing for the reputation of the author or the magazine. Grow up, or give up! There is no room for articles of this poor quality, content, or just plain annoyance on what should be a serious discussion with both sides plainly put, backed up by real world experience.

    I would suggest you give up your day job, and ride some to get some knowledge before you write again.

    Len in South Australia

    [Reply]

  23. seventhson on June 19th, 2012 11:30 pm

    I too have plenty of experience with a car tire on my Star Stratoliner (General Exclaim 205/55-17) It was a mistake….period. The wonderful handling of this low centre of gravity bike was no longer there. I have read from those who promote this foolishness that it “just feels different”….well “different does not come close to describing the way the straight line tracking is adversely affected by imperfections such as road patches, grooved pavement or lane furrows that are created by heavy truck traffic etc…etc…etc…Every day riding is just not as enjoyable with a square profile tire….here is why…
    With M/C tires front and back, your bike tracks a single line, but with the square profile rear tire you are now riding a narrow triangle. This is the source of ALL the straight line handling problems. Take the truck lane furrows that I mentioned earlier….the side of the square profile that is in contact with the furrow steers the bike in the opposite direction. In other words, when the left side of the rear tire is in contact with the furrow, your bike wants to lean right and vise versa To avoid this greasy, wobbly feeling, you end up riding the centre of the lane, where the pavement is somewhat flatter.
    My strong recommendation to less experienced riders…DON’T DO IT !!
    My bike also demonstrated a severe high speed wobble that was not there with a motorcycle tire. Those of you who promote this foolishness should keep you’re opinions off the internet….as you have no idea how a car tire might affect a motorcycle other than your own. Motorcycle manufacturers carefully select certain tires for their bikes. The choices they make come from hundreds of hours of R&D. The wrong tire choices can be adverse and worse…unpredictable and dangerous.

    [Reply]

    Rob Reply:

    Perhaps you chose the wrong tire to run on your bike. On gold wings the tire choices that are popular and work well are the Kumho run flat, the Perelli Euforia run flat, and the Michelin Primacy Alpin (winter snow tire). The Michelin is the latest most popular tire because of it’s rounded profile edge that many people are saying performs like a motorcycle tire. At least you tried it and found it was not for you…unlike the person writing this article.

    [Reply]

    seventhson Reply:

    So…. in other words picking the right car tire for my bike is a crap shoot. Maybe some riders are willing to compromise and maybe others actually have found the right car tire but from the extreme way it altered my bike I just think most dark side riders accept the handling compromises to save some money.
    I guess my main point here is that sooner or later….or maybe it has already happened….some poor sucker is going to install a the wrong car tire, hop on the bike and kill himself.

    [Reply]

    Rob Reply:

    I think most people these days know how to use a computer and can look up about the subject. In doing so they can come across forum that are for darkside riders. There they can ask all the questions and talk to people that run certain tires and make an informed decision from people that put thousands upon thousands of miles on these tires.

    Here is one of them for gold wing riders for example:

    http://gl1800riders.com/forums/forumdisplay.php?31-Darkside-Riders

    AS far as compromise…I really do not know of ANY compromise I am having to deal with with my tire besides at 5 mph it wants to follow groves in the road like coming to a stoplight. There is minimal more effort on turning and really I cannot tell much of a difference at all.

    I looked up all the information before I decided to go darkside and asked the people on the forum etc. The rest is history and I am happy with my choice.

    Arn Reply:

    Many a poor sucker have hopped on a bike and killed themselves, and not because of a d.o.t. Approved tire. I write from experience, I have put many miles on a cruiser of mine using a car tire on the rear. Now, I am on my second Goldwing, a 2012, and will continue this practice. I have been riding since 1972, and can tell you for sure that there are many safe habits one can practice that very well could save your life while cruising. There are many individual choices to be made, the right bike for you, fit, and what type of riding you enjoy. The choice to stay not only sober, but free of alcohol. I would think that with the huge possibility of harm while enjoying one of our favorite pastimes, then why would one injest anything known to slow down your response time ! Arn.

    openminded1966 Reply:

    I am not a darksider but find the idea and physics interesting. I have been reading a lot of the replies here and one point that needs to be brought up is that a car tire’s tread now a days is directional. So when it is mounted on a motorcycle, I believe it HAS to be mounted as if it was a left rear on a car. Mounting a tire so the tread and sipes are backwards would probably cause some of the handling issues you bring up and VERY bad in the rain.

    [Reply]

    Ken Adkins Reply:

    If you experienced wobble that wasn’t there previously, that should tell you that you either got a defective tire or it was not mounted/balanced properly. I have installed literally hundreds of tires during the course of my automotive career and have seen the end result of some very expensive tires that failed prematurely because they were not installed correctly or were new defects. I am also a rider spending $500 every 12-15 months for tires. There has to be a better option, maybe a car tire.

    [Reply]

  24. Auto Grip Tires on June 19th, 2012 11:53 pm

    a car tire on a motorcycle could not possibly be a good idea or a safe practice

    [Reply]

    Frank LeClair Reply:

    Thank you for your opinion, absolutely devoid of any experience or facts.

    The fact is that thousands of riders have tried it, for millions of accumulated miles, with no evidence of it being unsafe.

    Seventhson’s experiences he relays in a previous comment are one of the few negative experiences I’ve heard of. Myself, I’ve ran a car tire on the rear of my Kawasaki Vulcan 2000 for about 8000 miles, and the handling on highway ruts or uneven pavement is fairly minor and the only negative aspect I’ve found so far to the car tire.

    [Reply]

  25. Norm Spafard on June 20th, 2012 3:17 pm

    Having been around the block a time or two the only part of Eric’s article that has any substance is the first paragraph, which like a few other subjects will only bring out the worst and for unfortunate reasons. Not currently a DS’r there are a few points I take issue with on a diatribe such as this.

    First it is difficult to embrace such an article when it is presented so lopsidedly, opinion will never stand up to something well researched. Research in this situation requires something more than a few emails and talks with industry insiders. On example being the presentation of potential insurance issues, I made a quick call to my agent, who is with one of the nations top 3 insurance providers and he understood the issue and stated there was no weight to the potential of not being covered. Research is work and generally requires more than calls and emails. I doubt Rider does nothing less when performing road test and comparisons of equipment.

    Secondly, much ado is pushed on performance, exactly what are we talking about here? Aren’t the majority of motorcycle (and cars for that matter) engineered way beyond the max performance the average or even above average rider can use? Even if the average rider had the skills to maximize a bikes performance, where could they do so, not on any of the roads you and I use day in and day out. It seems fairly simple to deduce that even a car tire can handle any performance the general motorcycle population places on the average bike

    Thirdly, there was discussion regarding “handling differences”. So what does THAT mean; allow your tires to drop in pressure=handling difference; new tires vs old tires=handling difference; ape-hangers= handling difference, hard tail vs soft tail= handling difference, shoot cruisers vs sport vs touring vs standards = handling differences. You pays your money and you takes your chances.

    In conclusion, Eric wraps up saying he had done ‘due diligence’, personally I believe that from the responses here we can see that is far from the truth. Honestly the only thing accomplished here was mouthing the words of marketing insiders, we live in a world consumed with litigation, I doubt you can find one manufacturer of anything that would endorse the use of their particular product for something other than what it was made for. They can’t, it would open up a court room door. The by line of the article uses the word nonconformity, maybe it is about time to look at that word as something to embrace rather than ridicule, if my memory serves that was one of the principles that made this country great. Shoot to most of the driving public motorcycle riders are nonconformists to the max, DS’ing is not for everyone, so be it but lets not throw the baby out with the bath water simply because we heard it was the thing to do. Eric is a better writer than this and I believe that Rider is a better magazine than this, next time either go the full monty and truly do due diligence or allow sleeping dog to lye.

    [Reply]

  26. Larry Peterson on June 20th, 2012 3:29 pm

    After viewing the Rider magazine & website- It’s obvious why they won’t give a fair opinion on using a car tire.

    Motorcycle tire mfgr’s advertise on the website!

    Rider won’t bite the hand that feeds them.

    Where would this country be if everytime a new idea came up, we were told it can’t work! And we believed them!!

    [Reply]

  27. seventhson on June 20th, 2012 11:27 pm

    Hey look…I can understand trying to save some money by putting a car tire on you’re bike…I tried it myself with very poor and possibly dangerous results(bad straight line tracking and worse….severe high speed wobble), but to promote this foolishness on the internet as the answer to those evil tire manufacturers who refuse to make tires that last as long as these guys think they should?? Some of these guys are like religious zealots…disagree with them and their heads explode. I know that a lot of these guys say “it’s not for everyone” and I respect that…but please do not promote this as a sound alternative to dedicated M/C tires. Roll the dice for yourself but do not encourage others to. That is all I have to say….ride safe.

    [Reply]

    Rob Reply:

    Again…did you research for the proper tire? Did you go on forums and ask questions etc.? You make us out to be some kind of cult when all we all want to do is ride safe, not have our tires delaminate on us or get flat spots, and be able to bring us home safely. I can only speak for how it affects my gold wing because it is the only bike thus far that I have mounted a car tire on.

    On the flip side…just because you had a bad experience with the tire…doesn’t mean others will not have a great experience. That is why all of us should make INFORMED decisions on doing things with our bikes. In the end you will do what you want and I will do what I want.

    [Reply]

    Rick Reply:

    Yes; I get it that you tried DS and didn’t like it… I don’t like Bridgstone MC tires, so I switched brands for many of the same reasons you stated you don’t like DS tires… so what?? that doesn’t mean all BS tires are bad…. I just didn’t like them on my bike… your free to do as you wish… it’s just that your experience is so rare, that it causes suspicion regarding something you did wrong with your tire selection, installation, balancing etc… I’d look there first before dismissing DS out of hand

    As far as this article goes… it is the same old tired and moronic “Opinion Editorial” writing that is so common… he stated he believed it was a bad idea before he even wrote the one sided article and then set out to justify his “opinion” with “industry” experts who have a financial vested interest in maintaining the status quo… none of them stated they have ever ridden a bike with a DS tire on it and he never rode a bike with a DS tire on it.

    All of his self justifying opinions reached without doing any side by side comparisons of similar bikes with MS and DS tires on them to actually come up with any useable knowledge… worthless, worthless, worthless and he should be ashamed to claim the article is anything more than an OP-ED hatchet job piece of drivel.

    considering who pays his salary through advertisements in his magazine, I would have expected nothing less than this garbage…

    Give us some facts!!, side by side comparisons!!, tests of traction, cornering, smoothness of ride, stability etc on cruiser type MCs where DS is most often used… (not street bikes)… by people who are unbiased and are seeking the truth… please!!

    [Reply]

    seventhson Reply:

    Actually I did hunt around for opinions as to which tire to use and the Exclaim UHP was one that came as an excellent choice….obviously those who recommended it were willing to accept less than the best regarding handling and stability.
    BTW….you want an opinion on balls out board scraping handling?….That same tire was very twitchy at the limits. I now ride my bike with full confidence…something I sorely missed with the car tire. Sometimes you have to switch back just to recall what was missing.

    Also…I must say, Eric Trow’s opinions were just that….opinions…and I guess maybe he should actually climb on a Dark Side bike as a way to redress the comments of Darksiders that have commented here.

    So how about it Eric….
    will you give these guys an updated, educated opinion. As much as I dislike the Dark Side tire myself, maybe you’re the man to enlighten us all with an article/opinion with some personal seat time on the Dark Side.

    [Reply]

    rick Reply:

    I can’t disagree with what you’ve said here… you tried it and didn’t like it and you made an educated decision based on your experience… no one should question that.

    I was sceptical when I first tried a DS tire, but for me and my experience with two different DS tires on two different Cruiser MC’s for a total of 40,000 miles of riding on DS, I have been very happy with the ride, the performance and the longevity and have noticed with both bikes, that the DS tires stopped me quicker, held the road better on turns with wet or with sand/dirt on the road and gave me an overall smoother rode going down the road…
    I purchased both these bikes new, and replaced the original OEM tires with DS tires on both bikes when the OEM tires wore at at 6300 miles. The rate at which these OEM tires wore out was shocking! and I don’t ride that hard…
    I believe that if enough riders go DS on their Cruisers, eventually the MC tire industry will have to wake up and build tires for big heavy cruisers that get something close to 20,000 miles on a rear tire… until they do, they will see more and more Cruiser riders going DS….
    I know of no one who has had an accident/injury that was show to be directly related to using a DS tire on a cruiser type MC… does anyone??

    I believe that people who write articles for magazines with a bias, need to state it (he sort of does on this article in the intro) and if there was no research done, no new information brought out, no side by side testing done, then just state at the beginning of the article that your writing and OP ED piece about why DS tires are bad, so people don’t waste their time reading an article with NO useful information in it…. wouldn’t that be refreshing!!??

    Mad Meteor Reply:

    Seventhson,
    I appreciate the fact you tried a CT before climbing onto the anti-car tire bandwagon. However my experience could not be more different than yours. At this time I have a little over 101,000 miles on my 2002 GL1800, approximately 77, 000 of those miles have been done using four different car tires on the rear. I believe that I have given up nothing in safety, comfort or handling by using a car tire on my rear wheel. You feel your test of a car tire makes you an expert on the subject, my use of four different car tires over 77,000 miles makes me more of an expert on the subject than you.
    I admit that back in 2007 when I first heard about someone putting a car tire on a motorcycle I initially thought it to be a dumb idea. The more I read about it the more curious I became so, like you, I tried it. As it turned out, I liked it.
    You stated, ” I know that a lot of these guys say “it’s not for everyone” and I respect that…but please do not promote this as a sound alternative to dedicated M/C tires.” Fact: car tires work on many bikes and in truth they usually work quite well. That is irrefutable. Fact: there is nothing intrinsically dangerous about the practice or it would have become evident by now given the fairly large number of people doing it on a wide variety of motorcycles. It does appear to be a sound alternative to dedicated motorcycle tires in many cases. Every handling quirk, or characteristic you assign to your use of a car tire could just as easily been caused by a different brand of motorcycle tire or a faulty motorcycle tire. Not all car tires are alike just as not all motorcycle tires are alike.
    The fact that you have become such an ardent opponent to the use of a car tire on a motorcycle makes me wonder what your agenda really is. You charge others with extreme reactions. ” Some of these guys are like religious zealots…disagree with them and their heads explode.” Remember when you point a finger at someone there are three other fingers pointing back at you. I definitely see some zealotry in your posts. Is your head exploding?
    Listen, you didn’t like it, okay, others do. This country is supposed to be the land of choice. No one using a car tire on their motorcycle is harming you in any way so why all the vitriol? As far as anyone has been able to tell, no one has yet been harmed by the use of a car tire on a motorcycle. Fact: there are many far more dangerous practices than using a car tire on a motorcycle.
    The bigots of the world frustrate me. I’m going to get on my car tire equipped gl1800 and go for a ride. See you on the road.

    [Reply]

    seventhson Reply:

    Sorry, I refuse to let up on the C/T thing because you guys promote this stupidity on and on until someone is killed because he made the wrong choice. Explain your argument to those he left behind…..

    [Reply]

    Mad Meteor Reply:

    I would be overwhelmed by your compassion for motorcyclists and your quest to save the lives of so many that might be killed running car tires if only it were not so much hogwash. There are many things killing motorcyclists today but you can believe me when I tell you it is not car tires. If you’re really so concerned about your fellow riders why not campaign against those things that are killing motorcyclists? Why not campaign for mandatory rider education prior to getting a motorcycle license as Oregon and a few other states have done? Why not campaign for driver education so they might stop turning left in front of us or pulling out into our path of travel? Why not campaign for more rider education classes to teach riders how to brake, swerve and turn so they don’t crash trying to stop quickly or while attempting to avoid an obstacle? Why not campaign for motorcycle tires that don’t delaminate, split or fail while trying to put up with the stress of hauling an overloaded GL1800 down the highway with a trailer in tow? Why not campaign for safer guardrails and road barriers so motorcyclists don’t die when they run into them? Why not campaign for making ABS standard on every motorcycle sold in America? Why not campaign for stricter enforcement of distracted driver laws to help get the cell phone users and texters out from behind the wheel? These things, my friend, are killing multiple motorcyclists every single day and you are concerned about the one that hasn’t happened yet, and may never happen? Really?
    I certainly do have compassion for those “left behind”; I am a paramedic with over thirty years on the job. There is a good chance I have spoken to more of those “left behind ” than you have. I am also a rider course instructor. I try to do my bit to save lives by teaching riders how to stop, turn and swerve. I attempt to pass on these street survival skills to my students in an effort to keep them safe. Yes, I ride with a CT on the rear of my bike, that is my choice but I neither encourage nor discourage the practice to my students. If I sincerely thought it was unsafe I wouldn’t do it.
    You may certainly call the use of a motorcycle tire on the rear of a motorcycle ‘stupid’ as this is a country with free speech but saying it doesn’t make it so. You may call it dangerous but that is just patently untrue. You cannot make a logical argument that the practice has been proven unsafe. One could possibly argue that there is not enough statistical information to prove that the practice is statistically “safe” but I could just as effectively argue that the practice has so far not been proven to be statistically “unsafe” either. If you are really trying to prevent motorcycle deaths and want to spare those that are “left behind” from the real grief that comes from losing a loved one in a motorcycle crash, as I have, then focus your efforts where it might actually do some good. Until then you are just another sensationalist rabble-rouser shouting about a cause because it serves your ego. That’s fine, you go ahead. Remember the free speech thing? Just don’t try to paint your self as holier than thou with concern for all your brother and sister motorcyclists because it is not a suit that you could wear well.
    By the way, I’m teaching a class next month, if you would like to attend let me know and I will send you the information.

    seventhson Reply:

    Hey Look Mad Meteor my bottom line here is…do what ever you want…put a wheelbarrow tire on if you like…that’s up to you…but when it comes to promoting the use of car tires for others you C/T zealots should keep your foolish and possibly dangerous opinions to yourself. Personally I hope the DOT does a thorough investigation into this stupidity and starts restricting the use of tires not designed for motorcycles.

  28. Darkside contact patch vs Motorcycle tire contact patch.... videos - Page 5 on June 25th, 2012 8:32 am

    [...] 13,115 Good article: Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine [...]

  29. Mike mcdaniel on June 27th, 2012 11:20 am

    Hello fellow riders. I have read all the pros and cons of this topic. For two years now and about 22000km I have rode darkside on my Vulcan 2000 I would not go back to mc tire Handles just as well stops better feels much better in rain. And I pull a trailer as well. I say don’t knock it unless you have tried it. Mike Victoria bc

    [Reply]

  30. Steve Hobbs on June 27th, 2012 6:07 pm

    Interesting article but I have to call “B.S.” Nothing but opinion from someone who has no experience or test results to validate his point of view. I want a real world test with large, heavy cruisers. With 2 up. With 8000 miles on the tires. Riding in flat, no curves Florida in 95 degree temps and a sudden downpour. Riding down my loose gravel driveway. I run darkside, just came back from riding Deals Gap and found NO negative effects. I did find out my lean angle was greater than a dresser Harley and much faster even though the Harley had MC tires!
    I have a Victory Vision, ride 2 up alot, pull a trailer (not at Deals Gap).
    Please provide REAL WORLD test. (I know it will not handle like a Ducati but geez I can only lean over about 30 degrees)

    [Reply]

  31. Darkside report from Rider Magazine - Honda Shadow Forums : Shadow Motorcycle Forum on July 2nd, 2012 5:07 pm

    [...] report from Rider Magazine Here. Before you read it, you've got to know the magazine will come out against. It has to. There are [...]

  32. Jerry on July 5th, 2012 5:48 pm

    The world is run by lawyers. No tire co. motorcycle co., or engineer can come out and say it is safe to run a c/t on a bike without the risk of being sued by some other lawyer representing a greedy accident victim.

    [Reply]

  33. Sean "SPyKER" Kerwick on July 6th, 2012 8:57 am

    When I purchased my Honda 1300S, it was already outside of dealer specifications: wheels changed from spokes to rims, risers added, a windshield added, lowers added, fuel pump removed (the same Honda engineers who figured out the tire needs had forgotten about gravity, the 2003 was the only year they had a pump on a VTX 1300), pair valve blocked off to prevent backfiring, carb needle “shimmed” to get better horsepower and fuel efficiency (I now get 43 MPH), and it had a Brazilian VW car tire mounted on the back. It rode very well, handled well, and I loved the ride.

    A few months later I wrecked the bike when rear braking too hard on a hot road with “tar snakes”. I do not blame the tire, I blame my skill level. But at that time, I decided to have the rear car tire replaced with a motorcycle tire. My first ride around the block, the bike just dropped into turns unlike it had done ever before while I rode it. I liked it better, maybe as a fairly new returning rider, and have stayed with it. And I have stayed within dealer specs on the new tires, they are not manufacturer recomended Dunlops.

    Never did the insurance companies question the make or model of my tires in the cause of the accident, only checked the state of the tires, and verified that they were DOT approved.

    I have three rear rims in my garage now for the VTX: the one mounted with a Contienental Milestone motorcycle tire, and one to be mounted with a cat tire, and a wider one to me mounted with another motorcycle tire. I plan to ride the car tire on daily commutes, the stock size motorcycle tire on twisty rides, and the wider motorcycle tire on longer tours like the 1700+ miles I just complted, to help compensate for a larger load.

    To the manufacturer’s comments, no aftermarket part affecting performance should ever be sold. We all know that this is not going to happen, and each part that comes out has a group who adopt and test the results to a community. They are going to be more one sided because that is human nature, as are the manufacturers and scientists for the same reason.

    Until someone does a true scientific comparison across multiple motorcycles with multiple car tires under multiple riding conditions, we will never truely know the truth about “Darksiding.”

    [Reply]

  34. First Time Darksider -- Unbiased Initial Opinion/Perspective on July 9th, 2012 8:02 am

    [...] when the $h!t hits the fan and you're at 10,000 ft or 10 miles out at sea. Please read the article. Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine Mark Hagerstown, MD '05 Vulcan 1600 Classic "ad astra per aspera" Reply [...]

  35. First Time Darksider -- Unbiased Initial Opinion/Perspective on July 9th, 2012 11:51 am

    [...] when the $h!t hits the fan and you're at 10,000 ft or 10 miles out at sea. Please read the article. Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine No, the article didn't have any scientific data. It had statements from "experts" that [...]

  36. BigDawgB on July 9th, 2012 6:06 pm

    This was a total waste of my life to read.. Poorly written, totally biased and gave no real factual data. All you did was interview tire manufactures, motorcycle companies and so called safety “Experts”.. yeah, none of them are going to stick their necks out to endorse Car tires on motorcycles.

    I have over 30,000 miles Riding The Darkside.. (on one tire) I ride a 1999 Suzuki Intruder 1500 LC.. BIG bike.. and Im a big rider.. I have had my bike on every type of road condition except snow and ice. I have ridden the Tail of The Dragon more than 6 times and several other of the most technically challenging roads in the country. Not once did I feel uncomfortable about pushing the limits of the bike. She has been floorboard to floorboard and not a single issue..

    If you want to discuss factual information then fine.. go get some, don’t write an article based on opinion.. Lets get some true scientific data to discuss. The write an objective, non-biased, fact based article.

    Darkside tire: $98
    Mounting: $40
    Mileage so far: 32,244 mile.. with tread left for about 3,000 more..

    “You don’t know the power of The Darkside!”

    [Reply]

  37. Mark on July 9th, 2012 9:09 pm

    Experts built the Space Shuttle Columbia, Experts build the Twin Towers, Experts built the Titanic….Sorry…all the above experts did something wrong….Again…stop the opinions..Lets pick on one…IF so many people are buying Kumho tires to be placed on motorcycles….the question you should have asked was “Why is Kumho not performing official tests of their tire on Motorcycles…why are you passing up an opportunity to make good money and expand your industry?”….that would have given the real answer…..Again all your experts in the article could not provide any evidence that the tire is unsafe….

    [Reply]

  38. Mark on July 10th, 2012 6:18 pm

    The practice of running car tires on motorcycles has been well documented in the past. I ran a car tire on my VL1500 Suzuki with great results for comfort and even rode it hard through some corners with great traction and no hint of trouble. Perhaps you could use some real journalistic practices and do an UN-biased article with conversations from both sides and dare I say some tests? If you dare…

    [Reply]

  39. Dennis O. Johnson on July 11th, 2012 5:58 pm

    I have never been so disappointed by an article as I was this one. Frankly, it is not up to the standards I had expected from Rider.

    I have never used a CT on a bike, but have considered it and was interested in what I thought would be a thoughtful article, but instead found a rehash of opinions that appeared designed to please your advertisers rather than provide solid information for your readers. There are many other comments on the deficiencies of the articles and I agree with most of them. You should have done better than just present again all the old information and opinions.

    The reason I am interested is because I have seen a lot of sidecar drivers using CTs. If you think about it, having a round profile on the rear tire of a sidecar rig really does not make sense. A flatter profile, like in a car tire, provides much longer life and traction for a sidecar. I have had three sidecar rigs, and every one of them wore out the back tire in 4000 or less miles. This is ridiculous and why so may sidecar hacks sport CTs. The MC tires start to look more and more like CTs the longer you ride them. They just keep getting flatter and flatter, until the fabric is showing in the center. So why not just put on a flat CT in the first place?

    Most of the arguments that you presented just do not apply to sidecars and do not appear to be backed up by facts. Drawings are not facts. Neither are opinions. Reconsider this and try to do better next time.

    [Reply]

  40. Sean Manks on July 19th, 2012 2:55 pm

    I think this article should be a ‘wake up’ call to the MC tire manufacturers. The MC tires are way way overpriced than regular car tires. Plus, they aren’t even that long lasting as they are priced.

    It’s similar to buying a gps for MC that costs a lot than a gps for cars, the only main difference, the MC’s gps are weather-proof.

    The car tires are more stronger and long lasting than their MC counterparts.

    Will anyone buy car tires if they cost more than a couple of hundred (US) dollars EACH and can (maybe) last anywhere between 4500 – 10,000 miles only.

    The scientific breakthroughs in making of car tires have been very cutting edge than compared to mc tires (not wanting to start a huge debate here).

    On an average, my car tires have lasted around 6 years &/or 50,000 miles. Depending upon their rebate offers, I always purchase my car tires (reasonably priced) at Costco or BJ’s.

    But, my motorcycle tires lasts only around 8,000 (500-700+- miles) miles & have to purchase & replace them at the motorcycle dealer at a higher cost compared to my car tires. No I am not a rash rider who’s trying to kill himself out there by doing stunt riding.

    Lastly, was this story funded by the MC tire companies?

    Sean.

    [Reply]

  41. Letters to the Editor: Dark Side | Rider Magazine on July 20th, 2012 9:41 am

    [...] Tales From the Dark Side: Putting Car Tires on Motorcycles [...]

  42. Randy Button on July 20th, 2012 11:27 am

    Wow,

    What a great debate.

    I’m considering the Car tire on my Valkyrie.

    I bet I will like it, or I won’t. :)

    Randy.

    [Reply]

  43. Art Palmer on July 25th, 2012 4:35 am

    After careful consideration, I chose the darkside about 25,00 miles ago. I ran a Kumho RF on my 2009 GL18 for 15K+ miles and replaced it with a Michelin PA3 ZP for the start of the season in April this year. The Kumho still had about 3k miles left in it. We ride 2up in the twisties frequently pulling a trailer. No issues with these tires on this bike.
    I’m not proselytizing – check forums for real info if interested. If not interested – that’s OK by me…

    It’s a shock to the status-quo and our view of order in the world when people begin to discover the earth isn’t flat; the sun doesn’t revolve around the earth; and viruses and bacteria are the cause of disease notwithstanding what the “experts” opinion might be.

    [Reply]

  44. The Dark Side - Page 2 - Honda Shadow Forums : Shadow Motorcycle Forum on July 25th, 2012 5:11 pm

    [...] [...]

  45. fantage on July 26th, 2012 4:46 am

    it is a game or what I will see maybe it is not a game but I wish it is will be a game

    [Reply]

  46. Jim Benson on July 27th, 2012 11:28 am

    I appreciate the dialog concerning a car tire vs a motorcycle tire. Approaching my 3rd tire with only 17K miles, I have a 2010 Kawasaki Voyager. I had to do somelthing economical, thus I tried the General Tire Altimax 205-60-16.

    The downside has been the same others are experiencing: wiggle while navigating the grooves in the road. I had the same issue with a MT.

    The positive side: my bike’s speedometer is finally within a 1 mph variance, whereas with the MT it was up to 3 mph variance.

    I have only put 300 miles on the car tire, I usually average 1000 miles a month so I will know quickly whether my decision is a respectable one.

    So far I am happy, and if I get 20K out of this tire, I will be estatic.

    It would be nice to have a reputable company test the car tire side by side with a motorcycle tire. I am very interested in valid safety issues. Most car tire testimonies seem positive.

    [Reply]

  47. Dark Side Article... - Honda Shadow Forums : Shadow Motorcycle Forum on July 27th, 2012 6:52 pm

    [...] Side Article… Not poking the bear– Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine I was surprised to see a national rag take this up. __________________ Yup. That Capt [...]

  48. Ryan on July 30th, 2012 1:23 am

    Seems everyone here promoting the greatness of car tires on the rear seems to ride cruisers (big ones at that)… which IMO gives me the impression that they ride mainly freeways, for long stretches, rarely turning throughout their life. Fine… I can see a car tire working very well in such a situation…

    I, so far, haven’t read a comment from anyone in the crotchrocket, sportbike, dualsport, enduro, adventure, standard or dirt riding subgenres of motorcycling. Wonder why this could be….

    I ride a 2010 KLR650. From bikes in the past and including the KLR, when the MC rear tire starts to wear flat across the bottom of the tread, leaning into a turn (any turn where the lean is over 15 degrees) produces produces a definate shimmy as you rise up from the flat onto the edge… that really annoys me. Would I put a car tire on my bike, hell no! I enjoy the ability to ride the twisties with no compromise.

    I have come to three conclusions in reading this opinion/article and it’s comments:

    1) Got a big cruiser and lots of freeway riding? A car tire could be something to look into!

    2) Dunlop tires are crap!!! (experience talking)

    3) People who shell out big bucks $$$ (over twenty grand) for a nice cruiser with all the bells and whistles sure like to nitpick the minor cost of a tire…

    [Reply]

    Frank LeClair Reply:

    I do turn, and turn hard within the limits of my heavy cruiser. My Vulcan 2000 sharpens floorboards at pitiful lean angles, but I make up for it with full throttle rollons out of corners – My car tire (General Altimax HP) hasn’t even come close to its traction limits.

    Also, I’ve rarely heard of any Harleys running car tires, the rest of the cruisers are metric ones that aren’t anywhere near 20 grand.

    Yeah, this isn’t for sportbike riders, although I have heard of Yamaha FJR1300s mounting car tires and liking it. Inherently, a motorcycle tire will have better traction at high lean angles (such as with a sportbike) than a car tire, but at moderate lean angles, such as cruisers, in my firsthand experience the right car tire on the right bike has better traction.

    [Reply]

  49. John A. Stockman on August 2nd, 2012 1:43 pm

    You are free to run what you want. We all have our own unique experiences and economic situations that lead us to the choices we make. I am not going to be able to convince car-tire-proponents that they’re “wrong”, because of their personal experiences. If it works for you, do it…all this crowing on about “I’m right because I use one and like it” is meaningless. I’m not “wrong” because I choose to use, and happily pay for, a motorcycle-specific tire. I probably have less $$ to work with than a lot of folks. If some want to cheap-out and put a car tire on their machine, why do you care what others think? It’s your bike and your money, you are free to spend it on whatever you desire.
    Personally, after experiencing a ride on a VTX, V-Rod, Road King, GL1500 & GL1800 with a darksiders-forum recommended car tire on the rear, I would never do it on any of my bikes. My choice…it’s your bike, put a tractor tire on it if you want. I do get tired of people complaining about prices. Prices are the result of, and about, economy-of-scale, not some insidious manufacturer or a ridiculous conspiracy-theory out to personally wallet-rape you. If you’re interested in that scenario, all you have to do is work behind the counter (like I did for 20 years) at a brick & mortar old school stereo/audio store and see what speaker manufacturers get away with. When you only sell for example, tens of thousands of something, compared to a few millions of something,. it’s going to COST MORE to make and to buy. Motorcycling is small compared to the auto industry and it will always be this way. Motorcycle things are more expensive; parts, gear, service and TIRES. The old saying “you knew the job was dangerous when you took it” applies here. Sure you can economize when appropriate. I look for sales and good deals like most. One thing I will not compromise on is my ability to effectively control my bike and protect myself from oblivious car drivers, and not add to decreasing that ability. Which means I maintain my bike in top condition; that requires a bit more expensive oil and other consumables. My tires are my only connection to the tarmac and the only way to know what’s going on at the contact patch. Talk to Dave Searle at MCN about this issue, being able to have a decent lean-angle on your bike so you can swerve (lean over farther) if you encounter an obstacle or someone in your lane going around a corner. Sorry, but 25 or 28 degrees of lean-angle isn’t enough, like some of the Sportsters and FL chassis bikes I’ve ridden. I’m not referring to just sport bikes, either, as even riding at a moderate pace with some bikes uses up all the available lean-angle when cornering. For those that still believe the fallacy that advertisers dictate the editorial content, Mr. Searle doesn’t have to be concerned with advertisers, like some people have suggested that advertising influences moto-journalists and their writings. And the people that have asked “have you actually used a car tire or ridden a bike that has one?”, I will point out to you: has anyone who posted in this topic ever been a motorcycling journalist? Have you ever spent any time talking with or riding with them? This notion of “they won’t bite the hand that feeds them” is BS and could only come from a place of ignorance with those who have never been “behind the counter” at a motorcycle magazine. I’ve interacted with guys like Fred Rau, Don Canet, Mitch Boehm, John Burns, etc. Mainly because my unique situation as an oxy-moronic “handicapped” rider with an insidious degenerative joint disability, SEDT. Meaning I’ve endured a tremendous amount of challenges to become and remain an accomplished motorcyclist, and they were interested in my situation and what I’ve gone through. They do not kiss advertisers asses, nor are their opinions shaped or influenced by who or what is paying for pages in their respective mags. If you don’t believe me, have a talk with Clement Salvadori and tell him his writings and opinions are shaped by who’s paying for advertising. You guys don’t know what you’re talking about with that particular issue. Until you’ve been on the masthead of a motorcycle magazine, let’s dispense with that drivel. I could tell you things I saw concerning the popular, recognized speaker OEM’s that would cause you to never buy a recognized big-box-audio-store speaker brand again. The amount of lies and hyperbole is unbelievable. And the build-quality (cabinet construction) is poor because you never see the inside or have been able to aurally compare to something that has a substantial, braced cabinet and has a properly designed crossover. They’re sold based on aesthetics, marketing-speak, and much techno yak-yak, not how well the enclosure is constructed or how well the crossover was developed and implemented. What you end up with at your home has been compromised severely by bean-counters who strangle the designers & engineers who actually want to make something that sounds better. You don’t know it can be better because all you get to listen to and compare with is other compromised retail offerings.
    The car-tire guys, keep using your car tires. But after being able to ride those cruisers and two different Gold Wings with car tires, I will not be doing it. And I won’t ride with or next to anyone that runs a car tire after seeing how those bikes handled and how the individual pilots operated/controlled those motorcycles. Thanks for the opportunity to speak about my concerns. Just keep riding, that’s what it’s all about.

    John A.

    [Reply]

    John A. Stockman Reply:

    One other thing about credibility: David Hough has more of that in his little finger concerning this topic than any car-tire-proponents have in their whole being. Eric included David in this discussion because his words and experiences carry the credibility that is needed. That’s all I need. I had a chance to meet with and talk to Mr. Hough at a Seattle motorcycle function. His knowledge, experience and mileage on many different bikes including sidecars/trikes should have meaning here…something the CT guys conveniently overlooked. If you don’t believe or listen to David Hough, you’re beyond help, reason and common sense. Have fun saving some money. Put some loud pipes on your bike and subscribe to the other fallacy that “loud pipes save lives” to complete the lunacy. Thanks Rider, I won’t be childishly canceling my subscription because I don’t agree with something.

    John A.

    [Reply]

  50. Mike Upton on August 4th, 2012 8:58 am

    I have been running a General UHP Exclaim 205/50/17 on my DL1000 Vstrom for the last 500 miles.
    I like it!
    Is it for everyone, NO!
    I have slowed down in the twisties a little, but that has made my riding buddies happy.
    Iam only shooting them at 10-20 over the speed limit now!
    I have had one case of head shake but that was after passing a vehicle at around 80-85 and some wise ass put a rumble strip at the center line of the lanes.
    I have 2 Vstroms, the 650 and 1000 and the tires are definitely different to run from motorcycle tires.
    But depending on the riding application I find it no big deal.
    My 650 has 80/20 adventure type tires and my 1000 I have built for 1000 mile days.
    The Darkside will be my Alaska setup and thats what I have been testing it out for to see if its workable before setting out on a 3 week trip and decide this is not working.
    You will not find a magazine or company that will tell you it works and except that liability period!

    [Reply]

    Greg Reply:

    I just crashed my Ural but have bought a Suzuki 1000 vstrom to replace it .I am looking for a suitable car tyre to use on the rear drive on the bike & keep the bike front tyre & sidecar tyre at 19″.I have met an elderly gent that only uses spacesaver tyres to do same without a problem .This is not my idea of a good way to go.All I want is a tyre that will handle semi off road conditions & get good miealage with speeds rarely exceeding 70mph.

    [Reply]

  51. car instalation on August 6th, 2012 3:10 am

    I liked your site … I am very impressive to your work ,,,,,,,,,,,,

    [Reply]

  52. Jeff Popa on August 10th, 2012 8:12 am

    I’m not sure what the “tire patch” issue is about. I have seen videos where a rider has mounted a camera under their motorcycle and when they corner, the “tire patch” is greater on the auto tire than on the motorcycle tire. While I understand the differences in construction, if the amount of rubber on the ground isn’t important, then why not use thinner tires for better mileage with less rolling resistance? The video shows at least 2″ more contact area with the car tire, and while the motorcycle tire is shaped differently, even a car tire mounted on a car will roll to the side going around a sharp, fast curve. While I don’t claim to understand this argument totally, it seems that by talking to only motorcycle tire people, you are weighing the odds in favor of them, and the sale of their tires. Of course it will handle differently, different brands of motorcycle tires handle differently, duh….. And while some of us like a “spirited” ride through the corners, most luxury bikes spend their lives on the super slab, not the dragon….

    [Reply]

  53. Ken Hattan on August 17th, 2012 3:19 pm

    This video is much like what I saw riding behind an FJR on a curvy road. The CT didn’t slow down the other FJR and I didn’t see any problem regarding the tire holding a line or doing weird things in the corners.

    http://www.motorcycleforums.net/forum/off-topic/47922-darkside-contact-patch-vs-motorcycle-tire-contact-patch-videos-5.html#post667118

    Most people who respond on this list don’t give any personal information regarding their riding skill, longevity, level of experience or how many miles they ride, so when people post without some notes to their credibility, most every thing said must be taken with a grain of salt. Those riders that log over 30,000 miles a year may just command a little more respect than those that only ride 7,000 miles. Those that use a CT are different people, with different objectives but not necessarily any less concerned about their lives, or their passengers life, or even the expense of the tire. To assume either of these points is only a distraction and a waste reading time.

    With only 300K under my belt and only doing 20K to 25K a year, I do get tired of changing tires. I am on my third rear tire this year, which is my usual for a year. I would like a tire that would last 30K and be designed for a motorcycle, even if it was only recommended for freeway. Many of the long distance riders do most of their miles on the freeway, but do venture off for a good twisty section too. The market for long distance tires would be bigger if the Manufactures produced such a tire, but until then you will find people trying to make this work with car tires. I commend them for doing so and making the statement in a positive way. Now it is up to the motorcycle tire manufacturers to take note and do the right thing.

    It is also time for the Magazines to also provide respectable articles on this subject too. At least mount up a CT and test it. We all know you aren’t going to do this to a sportbike.

    [Reply]

  54. car tires? - Harley Davidson Forums: Harley Davidson Motorcycle Forum on August 26th, 2012 8:56 am

    [...] tires? just so you know, Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine __________________ 2009 crossbones. 2010 bmw r1200r. 2008 triumph bonneville with sidecar. [...]

  55. Larry Landin on September 9th, 2012 3:34 pm

    One of the biggest issues facing the argument is that engineers do what has historically worked and often miss the obvious because of it. As an operating engineer on a destroyer, I found a useless valve submerged in a fresh water tank. What was the valve attached to? A salt water line. The result was continually salting a 1200psi boiler. To put that in the words of Igon from Ghostbusters, that “would be bad.” When reported to SupShip, they maintained that it had to stay the way it was designed. Since they weren’t the ones that would go before a Courts Martial if the 1200psi system failed and killed a sailor, I had it changed. No more salting problems. Put a run flat car tire on your motorcycle and be safe. Let the pencil pushers believe they know it all.

    [Reply]

  56. Bob from SW Ohio on September 21st, 2012 2:03 pm

    I rode car tire on my BMW sidecar rig with a modified wheel. Rode great. However, I’m on my way to see a friend in ICU who was seriously injured when a car tire blew up when attempting to mount a car tire on a motorcycle rim. See Hillsboro Times Gazette for9/22/12

    [Reply]

  57. Rah on October 1st, 2012 1:54 am

    I own a 2007 victory jackpot. After only 6,000 miles on my current rear 250 tyre, I find that it is already significantly worn. My next tyre will be a 255/40/18 car tyre. I accept the judgements of those who have tried and succeeded. I congratulate you all.

    [Reply]

  58. Wilbur on October 8th, 2012 3:22 pm

    Let’s be honest… This really boils down to one thing and one thing only. People that are putting car tires on their motorcycle are doing it because it is cheaper. The tire manufacturers are telling you that you shouldn’t do it…the motorcycle manufacturers are telling you not to do it, and if you asked your average biker they would say “why the hell would you want to do that” . people putting car tires on their bike are cheap. a motorcycle tire is meant to be round not square end of story.

    [Reply]

  59. Don H on October 29th, 2012 2:41 am

    What would be the best car combo for a VTX 1800r 2004

    [Reply]

  60. Darkside, Just joined - Page 2 - Road Star Warrior Forum : Yamaha Star Warrior Forums on October 31st, 2012 6:38 am

    [...] to the forum and good luck with the car tire thing. Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine quotes: One Dark Sider proudly claims that on one forum alone there are more than 1,000 touring [...]

  61. BBunsen on November 9th, 2012 10:33 pm

    “Dare I suggest that it’s not unlike the way brain surgery calls for a specialist in neurology. Would you turn to a gastroenterologist for that procedure because he or she has a lower hourly rate than a neurosurgeon?”

    Only if I had my head up my ass.

    [Reply]

  62. Glenn S on November 19th, 2012 7:34 pm

    I put a car tire on the rear of my 05 Venture, and a rear motorcycle tire up front. I have 23K on the rear tire, without any problems. The only difference I found in handling is that it can get a little squirrely on uneven surfaces. Not a big deal, and I have never had a problem. I took the bike to the twisty roads of the Ozarks, and rode with a bunch of people on sport bikes. I had no problem keeping up with them and I passed a couple of them. The bike seem to grip much better in the curves than the motorcycle tire I had on before that. I suspect I will be putting a new tire on it this spring, but it’s still in good shape. I figure 25k or about that is good enough for the CT. I take a lot of long rides and want to make sure that it will hold up for 4k to 8k. Another concern I have with motorcycle tires is that if I am going to do an 8k ride, I need confidence in my rear tire. I would think I would have to get a new tire installed with the motorcycle tire after 6k. On the road that could be a problem. Not a problem with a car tire.

    [Reply]

  63. john geal on November 22nd, 2012 3:44 pm

    Hi i want to fit a 15 inch car tyre to my xv 1100 virago sidecar outfit as bike tyres wear out very quickly i have tried to fit one but it will just not pop up onto the last bit of bead even with plenty of lubricant &90 plus pounds of air pressure To confuse the issue even more i previously had a michelin car tyre on this same rim & that fitted ok ?? Any ideas anyone as i am reluctant to buy more new car tyres that wont fit thanks john

    [Reply]

  64. GENE on December 10th, 2012 11:23 pm

    Q.I GESS WHAT I’M ASKING IS THIS, I ORDERD A BRIDGSTONE TURANZA C/T 175-60-16 FOR MY 1500 GOLDWING, IS THAT A GOOD TIRE? OR SHOULD HAVE I GOT THE DONLOP? GOING TO PUT A BRIDGSTONE BATTLAX REAR 130-70-18 ON THE FRONT IN REVERCE. WILL THAT BE A GOOD WAY TO GO?

    [Reply]

  65. Darksides - Page 2 on February 20th, 2013 10:52 am

    [...] 94 Achievements: More info from a magazine on the merits, relative safety and basic engineering of CT on a MC: Tales From the Dark Side: Putting Car Tires on Motorcycles | Rider Magazine [...]

  66. Mike B on February 26th, 2013 6:13 pm

    As to credibility, I just wonder how much experience with a car tire on a motorcycle Mr. David Hough has. Possibly as much as could fit on the head of a pin?….. but that is just a guess though I think you see my point with that.

    About the whole kerfuffle about contact patch: The size of the contact patch per laws of physics is that it is a function of weight bearing down on the tire and the tire pressure to cause equal distribution of that weight. This; regardless of contact shape. If the weight bearing down on a tire is 300# and there is 30 PSI in that tire, then the contact area will be 10 square inches regardless of the shape it has or what kind of tire it is. Period. If the tire pressure is higher, then there is a smaller contact patch. Lower pressure would mean a larger contact patch. Of course there are practical limits to this for reasonable usability.

    what is important is the coefficient of friction. That is; how well it grips. Almost universally, motorcycle tire rubber compound is harder than car tire rubber except maybe in some specialized applications. I would venture then that softer rubber is better able to conform to irregularities in the road surface at microscopic levels providing a better grip. That is a logical assumption, but it would need serious testing to prove with absolute certainty.

    Car tires have higher load ratings than MC tires and cars put far greater lateral loads on their tires in turns than a motorcycle would ever be capable of. On a motorcycle, nearly all load is directed downward to the tread and seldom to across the width of the tread. So the sidewall would not likely ever get over stressed either.

    Bike riders regardless of their riding style, spend most of the time and miles riding in a vertical position so tread wears the center of the tire first. Consequently, there is unused tread uselessly remaining on a MC tire when a tire change is needed because of that center tread wear. That may be part of the reason for car tire longevity where most of the time the whole tread face is used to distribute load and wear and on a MC it is just wearing the center part of the tread. With a car tire, the tread area flexes so that in a turn, tread touching the road is parallel and in contact with the road while the rest is not; just as it would be with a MC tire.

    All of this and more from the guy who originated the use of a car tire on the 250cc Honda Reflex scooter and currently has 35,000 safe, trouble free miles on his 145/70R12 car tire on the rear and 17,000 miles from use of a Honda Silverwing scooter tire mounted up front. Both with many, many more miles of tread remaining.

    [Reply]

    Bruce Reply:

    “With a car tire, the tread area flexes so that in a turn, tread touching the road is parallel and in contact with the road while the rest is not; just as it would be with a MC tire.”

    I followed a GL1800 with a car tire across West Virginia and observed that the tread does not stay flat on the pavement when the bike leans. Only the edge of the tread was on the pavement so the contact patch was clearly smaller than a rounded motorcycle tire. This rider used low air pressure in his tire – the sidewalls flexed and squirmed like crazy – but beyond a certain lean angle the flat of the tire lifted off the ground.

    You talk about “regardless of contact shape” but a car tire’s edge is 90 degrees and the rubber is stiff enough to not flatten out when leaned over.

    All of the car tires that I have seen on motorcycles have rounded edges proving that they are riding on a narrow edge and that round is the natural shape for a bike tire. No, I am not going to try a car tire. What I observed scared me too much. I like to lean.

    [Reply]

  67. John McCutheon on March 2nd, 2013 2:40 pm

    I needed a tire that would give me at least 10K miles, loaded for a multi-month trip, two-up to Central America on my DL650. At the time, the ME880 was about the best mileage tire and even that wouldn’t do. I decided to try a CT even though I was very skeptical especially since I like to scoot along pretty fast in the corvers. At first, I was a bit disappointed as it was pure hell to mount but eventually with the help of a ratchet strap, I got it mounted. I can tell you this, with that CT on that rim,,,, there is no worry of some BS catastrophic bead flying off.

    Once I got it on, more disappointment. I was brow beaten by the internet Chicken Littles of the world into thinking those beads would pop off at the slightest provocation and I aired it up to the max pressure which was something like 45psi. Terrible,,,, I live on a 1/4 dirt road and immediately noticed that the tire width accentuated every bump, rock and rut. Got to the end of the dirt road and lower the pressure to 40psi. Road about 15-20 miles and while better, still hated it. I then lowered the pressure to 30psi and low and behold,,,, it’s started getting better. At this point I was on my beloved “Loop” which in N. Ga. is Hwy 60 to Hwy19, then Hwy129, then Hwy180 and finally back to Hwy60 and in between, quite a bit of rough dirt roads for some off tarmac testing.

    I lowered the pressure to 20 and then hit some dirt road mileage. Better but then I lowered it to 15 and found that too low even on the dirt. While the CT’s manners were much improved, I still don’t like it as much as my normal Shinko 705s or TKCs or Big Blocks. But,,,, I hit the tarma again and aired back up to around 25psi and honestly,,,, I was very surprised. Yes, the CT slows the steering input down a bit and it takes a smidge more muscle than a 705 but anyone that has ridden a DL with 705s knows the front 705 is a very quick and light steering front so the CT on the rear actually results in a more “normal” feel.

    My DL is heavily modded with DR front forks and a custom rear shock, I’ve raised the bike around 1.5-2 inches and has a couple inches more travel than OE. The front forks have a set of modded Intimidators and stiffer springs. The rear shock has about an inch more travel and is stiffer than OE as well. In all honesty, this DL is worlds better than the stock DL. I use the bike hard in the corners and when it was stock, I could easily drag the pegs in pretty much any corner from a tight 20mph hair pin to a 90mph sweeper. With the added couple of inches of height, dragging the pegs is no longer an issue but I still tick em down from time to time. I added this to help illustrate how this bike is used. It’s not a DL that you see diddling along holding up RVs,,,,, more often it’s railing along trying to play with the squids on their Gixxers then peeling off on some rocky, rutted rarely maintained dirt road to play adv rider with KTM Adventures.

    With that said,,,, after a bit of a learning period and gaining some confidence, I will say without hesitation that I love the CT on this bike in this application.

    Fact,,,,, all motorcycle tires force compromise. If you want mileage, you are forced to deal with low traction and often,,, less than stellar handling. The ME880 suck in the twisties and on dirt and I hated it in the rain.

    If you want a tire that will handle and stick well while you are playing make believe Rossi with the squids,,,, well you are lucky if it lasts longer than 3K miles and it too suck in the dirt.

    My favorite tire for this bike are the Shinko 705s and I often run a TKC or a Big Block front with a 705 rear for playing around locally. Still enough traction to have fun in the corners yet works “OK” in the dirt and will last around 5K miles when playing locally.

    For touring I run 705s front and back and combined with high air pressures and a soft touch on the throttle will return around 8-9K miles.

    Welp, my CT experiment went over 13K miles while playing and commuting locally which is at least double of a 705 used in the same manner. Matter of fact, I was exceptionally hard that tire and wore a brand new, installed at the same RK chain which normally, will last over 20K miles! In other words, if this CT were used in a purely touring application, I have no doubt it would have lasted at least 15-20K miles which is what a front 705 is good for if ridden conservatively.

    This is no bull, the CT gives BETTER traction than the tire I normally run, the 705. It gives better traction while straight up, braking, accelerating. It even gives BETTER traction while heeled over, draggin a peg and accelerating outta tight curve. While it doesn’t “handle” as well as even a 705 when really hauling the mail, it does give better traction. Read that again, better traction while heeled over. My bike, being better suspended and being a couple inches taller has much higher limits before dragging the pegs than a stock DL so do try to convince me that a CT is more dangerous “if all of a sudden, one has to make hard steering correction in an avoidance maneuver”. It also give better traction in slick conditions like in the rain or the snow {yes,,, I ride in the snow on the few occasions we see it}.

    In the dirt, the CT actually gives good traction on regular packed dirt roads. Better than even the 705s, maybe better than TKCs or Big Blocks. But, when the going gets muddy the CT sucks. When it’s sandy, not too good either but better than the 705 I think. When it gets really rough on rarely maintained dirt roads {thing Jeep/4×4 trails}, every big rock and rut upsets the bike because of that huge CT’s width. Not as bad when the going gets faster but at the very slow speeds where a bike like this would be on roads like that, it can get aggravating, especially at 1st during the learning curve. I learned to ignore that after awhile.

    The bad,,,,, well, there are a few draw backs JUST LIKE ANY OTHER TIRE CHOICE. First off, there is that rough dirt road handling. Most street bikes and even most DLs don’t go off road in places like that so to most, that’s not a biggie.

    The CT weighs alot. Tires that weigh alot just don’t handle as well due to the high unsprung weight. You really notice it in washboard dirt roads but you also notice it when really hauling the mail.

    That weight also effects acceleration. I thought the Big Block weighed alot but the CT alone probably weighs what most bike tires and wheel combos weigh. It will feel like you lost 5-10hp.

    But honestly folks,,,,, this is a DL650. It’s the SUV of the bike world and in that context, losing a smidge of acceleration, a smidge of handling at the very outer edges of what the bike itself is capable of both off road and on is more than a good trade off for more traction on road, most of the time off as well, longer life, like 2-3 times the life and overall durability {the CT will scoff at rocks and road debris that would damage a bike tire}.

    Would I mount a CT on a Gixxer and play Rossi? Nope.

    Would I mount a CT on a KTM Adv and do the Trans American Trail? Nope.

    Would I mount a CT on a Wing or a cruiser? Yep, in a minute.

    Will I run another CT on my DL or experiment with one on my FJR? Absolutely!!!!

    [Reply]

  68. Bill on March 5th, 2013 11:55 am

    I ride with a group of rider that use car tires (together we have over 150,000 miles on car tires). There have been no failures and we frequently drag the footpegs in corners.

    After the group experienced 3 tread separations on MC tires I contacted the manufacturer to see if there was a problem. I was told the tires should not be used on a goldwing in extremely hot temps, should not be used if the bike is over weight (many goldwings are), and should never be used to pull a trailer (many use trailers even though they are not recommended by the motorcycle manufacturer).

    With a car tire I get better handling of the weight, it runs cooler, and has never displayed any problem with trailers.

    By the way If you price a few runflat car tires they cost as much as MC tires (although they do get about twice the mileage). Cost (at least with me) is not the issue, safety is the only issue.

    Since we have had several tread separations (3) with MC tires and absolutely no problems with car tires, I choose to run what I believe (from experience) to be the safest tires for the way I ride (frequently 2 up with a trailer).

    If they ever develop a MC tire that will actually function in the real world for goldwing riders I’d be glad to switch back.

    We all have our opinions and this is mine…

    Thanks…….Bill

    [Reply]

  69. Philip on March 7th, 2013 1:35 am

    There is a new video just posted on this issue at http://www.tiretony.com. For those interested in a clear presentation on the Darkside, check it out.

    [Reply]

  70. Axzl on March 7th, 2013 7:53 pm

    Funny how all these “dorksiders” sing the praises of a square tire on the back but none of them would risk one on the front! What’s good for the goose should be good for the gander, right? The certain fact is, they’re unsafe at any end and at any speed, and on any motorcycle.

    [Reply]

  71. Peter Holzberger on March 12th, 2013 3:20 am

    Well fellers I am coming at this from another angle, I am riding a v~star 1100, but with a side car mounted at all times. We have one for around town & short trips & another larger car for touring , now as I am not using the muched aruged point that car tyres are not suitable for bikes because of contact surface being so different in cornering on a solo bike.

    But again today I have been to several bike stores trying to buy a rear tyre & at all these stores I have been urged to fit a normal morotcycle tyre.

    Now what the hell, we do not lean we are not riding a two wheeled machine we steer into a corner. Yet all these companies will not even consider a car tyre being fitted !

    My last tyre lasted ? 7000 k & the only section of the tyre that had any wear was approx 50 cm each side of the centre of the tyre outside that it still had the nipples attached ( no wear at all )

    So Rider ask your tyre manufacturing people what they think

    [Reply]

  72. Josh on March 15th, 2013 12:02 pm

    Makes me wonder if the author of this article ever looked through the owners manual of any motorcycle. If he had he would have clearly seen statements from the manufacturer about making modifications.
    I have seen this magazine promote all sorts of modifications like raking a front end, towing a trailer, aftermarket shocks all of which manufacturers have stated not to do. Clearly, the hypocritical statements made in the article were not on any of minds of the Riders staff.
    Technically aftermarket shocks would change the behavior and characteristics of the bike. So by this authors own logic should not be done.
    I inherited my cruiser from my father who had a car tire on it. Without even knowing the controversy have put over 15,000 trouble free miles on it.
    I am very saddened by the bigotry shown here by the author and by Rider. . My suggestion to Rider would be to first try something before making a final judgement on it.

    [Reply]

  73. Motorcycle Tires: Bias VS. Radials | Motorcycle College - Your motorcycle resource center on March 23rd, 2013 1:20 pm

    [...] Rider Magazine: The Dark Side [...]

  74. Phil on June 1st, 2013 4:29 pm

    Rider Needs a New Writer – Nothing Stated came close to reality.

    One would think you were only on 50 degree lean BMW R1200 – or – R1 , vs limited lean Cruisers of 30 degrees.

    That’s the biggest pile of FUBAR ever read as certified Honda Dealer Tech the last 35 years.

    [Reply]

  75. Rick on July 23rd, 2013 5:32 pm

    Sometimes, I think that there is a limit to human foolishness. Then someone ups the ante.

    [Reply]

  76. GENE CARLSTON on August 12th, 2013 11:21 am

    WHAT SIZS MICHELIN APLIN DO I PUT ON A 03 GOLDWING 1800,

    [Reply]

  77. John Hayes on September 9th, 2013 12:40 pm

    I think this article is pathetic. It is oh so similar to another that I read on the issue. It cites the opinions of experts on the practice of using a car tire as the rear tire of a heavy motorcycle as the final arbiter of the issue.

    We are talking about a resource to motorcycle riders. Motorcycle product reviewers whose JOB it is to investigate possibilities when it comes to motorcycle products and motorcycle practices. While the subject is NOT a motorcycle product, it IS a potential motorcycle practice.

    While it is true that the only folks championing the use of car tires as rear motorcycle tires ARE those who are doing it in a purely anecdotal way, that is the only information and resource available that offers ANY information on the subject of usage from an experiential perspective. The small amount I have read appears to be positive and in my mind, bears ALMOST as much weight as the reviewers regurgitations of the engineering experts that strongly discourage the idea. More research of anecdotal report reports that reveal no glaring safety reports will probably convince me give this idea a try.

    I know at least five folks personally who are doing this and none of them are speaking of a down side. They mention a few practical considerations, like a need to slightly over inflate you tire by 6 – 8 PSI.

    Why would I consider this?

    I just put new tires on the front and back of my 1999 Yamaha Royal Star Boulevard and with 5 thousand miles on them I realize that I’ll only get about 5 more thousand miles on the back tire. Wow, 10,000 sounds like a lot of miles. Ya think. I get maybe 30,000 on my car. It costs me about $100 to replace and installed. If I shop on the web for some bargain tire (like I did) and get a Shinko, maybe I can get it for about $100, then it will cost me at least $60 to have it installed. If I get a Dunlop, it will cost at least $150 if not more and I could pay up to $78 to have it installed.

    OK, when I replaced my tires in June, I did it myself. I figured I could save a LOT of money on the installation fee – but I had to BUY a few tools. So the first time cost a LOT more. I couldn’t buy the tire machine because it cost too much – but I probably will. I spent two entire days changing two tires. Doing it by hand with levers is a LOT of work and even though I tried to be careful I ended up having to replace two brake disks, so now my do it your self job got even more expensive.

    I figured that if could do the job myself and could get 15,000 miles on the rear tire I would be good. But now I see that the rear tire may only last about 6 months. That’s right, I put 16,000 miles on a motorcycle over the past 12 months.

    Considering the life expectancy folks are reporting for car tire usage as rear motorcycle tires we are not talking chicken feed here! We are talking about the difference between replacing the rear tire 2X a year as opposed to once every 2 years with a minimum of 1/4 the cost of rear motorcycle tires over a 2 year period. We are not talking about a few dollars difference. When the EXPERTS quit marginalizing this issue folks may START to give their advice more credence.

    Oh by the way, my front motorcycle tire WILL probably last 2 years!

    You folks are disgusting. You could do REAL research on this idea which would make your publication more valuable to your patrons, BUT it would cost money to do it, it would take time to do it AND the motorcycle tire industry would not pay you any money to do it.

    [Reply]

  78. Doc on September 10th, 2013 12:14 pm

    There are at least two locations on the internet where car tire users are collating data of usage. One is the ‘darkside’ on the GL1800 forum.
    http://gl1800riders.com/forums/forumdisplay.php?31-Darkside-Riders

    The other is on the Delphi Forums Darksiding forum.
    http://forums.delphiforums.com/DarkSiding

    The database is growing. There have been few documented cases of car tire failures (each appears to be extreme wear). There have been no accidents attributed to car tire use.

    I used car tires (actually small trailer tires) on my scooters in the fifties and early sixties (Cushman and Vespa). I put a car tire on a drag bike I built in the midsixties.

    Currently, on my new 2012 Goldwing, I picked up a big, ugly, screw in my rear tire. After reviewing the data, I replaced it with a Michelin Alpin PA3 ZP (run flat). It provides equal or superior cornering ability. It is noticeably better in stopping ability. It rides on gravel more sure footedly. My wife likes the more comfortable ride, which is the norm for passenger evaluations.

    I expect to get 20K miles out of the tire, even though I tend to be harder on tires than average. On my Valkyrie (owned it for 10 years), I tended to burn front and rear tires about every 5,000 miles. I’m a little more sedate on the Goldwing.

    But, with the run flat, I don’t expect to have an explosive decompression at speed. I have peace of mind, knowing that there isn’t a documented case of a car tire shredding like a bike tire does sometimes. And, with the run flat, I can ride for at least 50 miles at 50mph. That’s listed for a car. On the Wing, I might get twice as far. That can certainly be a trip saver when riding in the remote sections of the country.

    I’m so pleased with my car tire, that I will be ‘double darksiding’ when the front tire needs replacement. I will use a thicker treaded rear tire on the front. More tread equals greater safety! And longer tread life.

    [Reply]

  79. Jeff on September 14th, 2013 7:46 pm

    Like a lot of magazine articles. No experience in the subject, just fluff!
    If you want useful information, you need to read the forums and get first hand knowledge good and bad.
    Magazines are best for the pictures, not information.

    [Reply]

  80. John Hayes on November 19th, 2013 8:21 am

    For those who think the darkside is not for sportsbikes, think again. I don’t own a sportsbike, but while researching the idea for use on my cruiser, I ran into this:
    http://www.youtube.com/watch?v=NYhkCA_JwJM

    This guy is doing just FINE running a CT on his sportsbike. It corners as good as the best of them!

    Now I have put a CT on my 1999 Yamaha Royal Star Boulevard and just LOGGED 1000 miles. I don’t just ride down straight of ways on the free way. I like cruising the back roads better and the twisties are the BEST! I’ve leaned far enough to scrape my floor boards a couple of times. Once on an MT and once on my CT!

    Here are the truly notable design difference between a CT and an MT:
    - the beads are different so you may want to check your air pressure regularly. I check my tires daily by “kicking them”. Now laugh. After a month of riding on the CT (putting 1000 miles on them) they are still nice and hard. This weekend I’ll be the pressure gage out and top them up if necessary.

    - the side walls on a CT are not as rigid. You may notice a wobble when cornering. You correct this by putting another 6 – 8 PSI of air in your tire. I was told this by a Gold Wing owner who was darksiding. I started out with about 5PSI over. I noted that and called it good. I’ve NEVER noticed a wobble.

    - car tires are made of SOFTER rubber! Some folks think that CTs last better because the rubber is harder. Of course this would mean their traction is worse than a motorcycle tire. But it is NOT the case that CT rubber is harder. I asked a Car Tire Dealer, Budget Tire to be exact, the folks who mounted my CT on my motorcycle wheel! They said that CT rubber is softer that MT rubber AND winter tires are made of the softest rubber of all. So WHY do CTs used on motorcycle wheels last longer? Because they have a broad flat area that grips the road better (and softer rubber helps with that grip) providing less slip during acceleration and LESS LOSS OF RUBBER.

    - Oh, I forgot about the LEAN issue, i.e. camber thrust, one track vehicle steering. The factory spec for my tire size is 150/90-15 for the rear tire. For the front tire it is 150/80-16. The left most number is the width of the tire. The number on the right side of the “/” is the aspect ratio. It refers to the height of the tread above the start of the side wall as a percentage. The number to the right of the – is the radius of the wheel. For the car tire I used this sizing?: 165/80-15 for the rear tire. Note that the tire is 10 mili-meters wider so the difference in height between the top of the tire and the beginning of the side wall (the working part of the tire on the side) will be ABOUT THE SAME. Which SUGGESTS THAT THE AMOUNT OF LEAN YOU HAVE WILL BE ABOUT THE SAME! See the youtube video above.

    The only REAL difference in handling that I can tell was noted above by somebody who tried a CT and after a while went back to an MT. On the switch back he noted that he really had to go back to the MT to catch the way the bike just dropped into a lean on the MT!

    This is a no brainer folks! Look at the bottom of a CT and note how broad it is and how the edge quickly wraps around and heads to the side wall! But is this a huge issue? No! When I first started riding with a CT I BRIEFLY noted that it took a bit more effort to initiate a lean! It didn’t take but a couple of times out and now I am 100% used to it and totally do not think about it! It corners as good as it ever did! I love it. I spoke to a guy who had darksided for a number of years before discontinuing that practice. He made the same observation (and our friend above) made about the lean initiation issue. Why did he discontinue darksiding? Let’s ask a reciprocating question, why does anybody start darksiding? Because you are putting many thousand miles a year on your bike and do not want to replace the rear tire multiple times in one year! The guy that quit no longer had a need for that high mileage of a tire. He had several close calls in recent years due to car drivers pulling out in front of him and so he cut way back on his riding. At one time this guy told me he put 37,000 miles on his bike in one year. Me, I put a new tire on in June and placed it in September. I live in Michigan but ride all year.

    Darksiding is not for everybody. if you only put 5000 – 6000 on you bike a year you’ll probably be replacing the rear tire annually which is not too bad.

    CTs and cornering are NOT a big issue:
    http://www.youtube.com/watch?v=qoNDo7o1d6Q
    http://www.youtube.com/watch?v=F5YnEuGHXPo

    When you replace a motorcycle tire you will always have to get used to the way the new tire handles whether it be the same brand or a different one. They are ALL different.

    The difference in cornering between a CT and an MT are not an issue. And the softer rubber of the CT enables it to get a better grip when cornering. If you understand and have mastered the concept of counter steering you can drop your bike into any lean you want.

    The folks who make MTs COULD make them to last longer by making them wider, and with a much broader working face and a fast shoulder drop off LIKE A CAR TIRE but with a bead and side wall made for a motorcycle BUT t hey are not going to do that! Why? Because most of these same companies make car tires TOO and they know that a small group of brave belligerent people will use CTs on their bikes but the rest will listen to the advice of EXPERTS (their marketing shills) and do the appropriate thing! I mean after all, if you only put 5000 miles on your bike annually, a CT on the back will probably last you four years minimum and golly, where’s the profit in that?

    If you are inclined to try a CT on your rear wheel, be advised that not all CTs will work. You can refer to the following site for a list of tried tires for your bike:
    http://darkside.nwff.info/

    For some pointer about installation, this video may be helpful:
    http://www.youtube.com/watch?v=rjHwQHs-rlo

    The best thing to do is to have them installed. Find a Car Tire shop that is not afraid to do what you want. Something not quite main stream is probably what you want. Make some calls and ask some questions. They had to hit 116PSI of air in my tire to set the bead!

    [Reply]

  81. Eric V on February 5th, 2014 11:02 pm

    Figured it out yet, Mr. Trow?

    You lack knowledge and experience, and it shows. I applaud you for having actually gotten in print. But not for your content. You failed to adequately research the topic and spewed forth only your opinion, with out backing it up with any factual evidence or testing.

    And your opinion is wrong. Frankly, I only went to the darkside for one reason, motorcycle tire manufacturers stopped making tires that lasted more than 10k miles. And discontinued tires that did. Motorcyclists have been fooled into thinking that 4k miles is acceptable tread life. It’s not. Especially for those that ride 30-50k a year. The old bias ply motorcycle tires lasted 20k or more. A good car tire on the back of a powerful sport-touring bike will still last 40k miles. And provide all the grip to drag hard parts if the rider so chooses, as well as providing better tracking in marginal conditions.

    To the motorcycle tire manufactures, STEP UP. Provide tires that last, that still perform. Longevity and performance are not mutually exclusive aspects. Stop wasting time with race spec tires for sport bikes when no rider can make full use of that on the street. And when your “newest” generation of tire performs worse than the last, STEP UP, and discontinue the “newest” tire and bring back the previous version. Or, just maybe, use actual testing to determine what your young engineers have thought up before bringing it to market.

    You waste our money, we will stop buying your products. Never, ever forget that. There are alternatives.

    [Reply]

  82. Doc on February 7th, 2014 7:54 pm

    Eric, you pegged it! I remember when auto manufacturers swore that fuel injection would never work because it was too complicated for every day use. Spark plugs once lasted only five to ten thousand miles, if you took good care of them and constantly adjusted their gap. Other ignition components often lasted for shorter periods (points and condensers). And most cars and motorcycles needed top end work (valve jobs) at 20-30K miles.

    Now, today, we have plugs that last a 100,000 miles. Ignition components last the life of the car’s body. Fuel injection is not rare, it is common. And engines can easily go 150,000 or 200,000 miles without touching the valves.

    So, your point about purposefully limiting the life of motorcycle tires is dead accurate! Oh, yeah, I run a Michelin Alpin PA3 ZP (run flat) on my 2012 Goldwing. It sticks FAR better than the original OEM tire, and I expect four times the mileage out of it. And it is more puncture resistant. And it won’t disintegrate and put me face down on the asphalt. It is a top quality tire, so it cost about the same as a motorcycle tire, initially. But the much longer mileage drops the price to 25% or less than a motorcycle tire…and even lower if you count mounting costs.

    [Reply]

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