car tire size for Vstrom ??? (Pros and cons of car tire on a bike)

Discussion in 'The Perfect Line and Other Riding Myths' started by Jimm Dandy, Mar 27, 2012.

  1. Pecha72

    Pecha72 Long timer

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    Car tyres on motorcycles on accident investigations, and how it all goes with the insurance companies (or when possibly going to court), that's still a valid question in my view. At least to be aware of, and not just think it's okay because some guy on the internet claimed it is.

    The US is the promised land of lawsuits, I somehow find it difficult to swallow that nobody cares, if your tyres are legal or not in a situation like that. In Europe, they would certainly look at that very carefully.
  2. mrphotoman

    mrphotoman Long timer

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    It is terrible that dangerous information like this is spread on the net that risks the lives of those with a lower intelligence level.
  3. Jud

    Jud Long timer

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    We are aware of it, people like you will not stop harping on it. But this is the truth, alot of people use CT and I have never heard of an issue. No beads fly off, no terrible fiery deaths, no tickets and no insurance companies crappin in no-one's cornflakes. In some parts of the world, sometimes individual freedoms are trampled in the name of supposed safety for everyone. Hell, I've heard that in some countries you are not allowed to make any modifications unless the government approves it. Some countries don't even allow people to do their own maintenance unless they are approved repairmen. Just because "that the way we do it here" will not allow you to have an open mind and experiment doesn't mean it's like that everywhere. The US is fairly free on these type issues but little by little, the BS is creep in thanks in part to the same closed minded attitudes being thrown about in this post. The "I don't think it's safe, let's ban it" crap. In many parts of the US,,,, you don't have a vehicle inspection program and guess what,,, I like that. Maybe you and some other's wouldn't.

    Yes, you are right about one thing, this is the Land of Litigation and still,,,,, I haven't heard of anything like what you and supposedly others are worried about actually happening. First, even in the land of litigation you still have to prove that whatever you did {mount a CT on a bike} is the direct cause or majorly contributed to the accident. Second, no matter what the nervous ninnies are saying,,,,, running a CT out back is a fairly common thing especially with the Wing, Valkyrie and the other touring and cruising crowd. And guess what, the terrible things that some pontificate upon just are not happening. People are running a CT and many times depending on the application,,,,,, are getting more traction than the MT they were running, they are getting much better mileage and they are doing it safely again,,,,,, in direct contradiction to what all the naysayers are crying on and on about.

    Geeze man,,,, unlike the opposition, we have tried it and actually have experience to draw upon. We are not all lying about our experiences just to make ourselves "feel good". We have repeatedly said that running a CT isn't without some compromise. We have repeatedly said it isn't for everyone and we have repeatedly tried to answer your repeated questions on the issue of insurance and liability here in the US. Just feel good that you have brought up "what might happen" and move on. You are not a troll like some in here but dern man,,,,, let this issue go why don't you? It's getting old. :huh
  4. PhilB

    PhilB Long timer

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    I could see the value in going to the darkside for serious winter riding, since you (pretty much) can't get snow tires for bikes. You can't lean much on snowy/icy roads anyway, so a DOT knobby on the front and a car snowtire on the rear could make sense. Other than that sort of specific application, though, car tires on bikes don't make engineering sense. Cars and bikes are very different dynamically, and their respective tires are designed and constructed differently based on the different loading and different stresses of the respective vehicle types.

    PhilB
  5. Hoppalong

    Hoppalong Adventurer

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    When ancient space aliens visited Earth they used car tires on their motorcycles. And so do our current space-alien abductors. And so does Bigfoot. If it's good enough for them, it's gotta be good.

    PhilB, never let logic and facts get in the way of a good story.
  6. kingby

    kingby Adventurer

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    Did any of you read this?? The type of rim and the load forces/directions each type of tire is designed for are the two big differences. Conclusion, ct's for cars and mt's for bikes. Just the really poor way the ct bead sits on a motorcycle rim, scares the bejeesus out of me. But I am just an engineer, so what do I know.
  7. randyo

    randyo Long timer

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    The insurance question has been asked and answered by several insurance companies , if there is no specific exclusion, it's covered

    I went to the darkside as a winter experiment with no expectations, it was successful beyond my wildest expectations, with a winter car tire mounted on the back and a studded knobby up front, even riding in blizzard conditions

    my initial intent was to go back to a MC tire during the other 3 seasons, but other than single track, I like the performance of the car tire better, and most especially in the wet
  8. Jud

    Jud Long timer

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    I apologise for the "Wall of Text". I know it's alot to read but I'm trying to be open, honest and address legitimate points raised in this debate. I simply do not think a single sentence or paragraph would address that.


    I read/scanned through most of it. I'm betting Bluelightning did too. In case you simply read it without applying common sense and real world practical knowledge to the hard data presented-

    The tire bead consists of a steel or synthetic fiber cord and rubber composite. It's not a hard piece of steel. The rubber isn't hard steel, it can and will conform to minor differences in bead lip shape and I think the differences between the CT bead and the motorcycle rim are well with-in the capabilities of the CT's conformance abilities. Production tolerances being what they are amongst different rim and tire manufacturers, I'm willing to bet there is nearly as much different in bead lip diameters and widths between MT rim and tire widths as there is between MT and CT bead and rim lips. Anyone that has done any amount of bike tire changes has experienced this very thing. Some tire and wheel combos, the tires slides on like butter and removes the same. Some are a pain in the ass to mount, hard to get the beads to "pop" and are a pain to get the beads to "break" for dismounting. I've had enough tires go flat that I feel I have enough experience to say that generally, the MTs that are super easy to mount and the beads popped easily are generally the ones that are dangerous once you have a complete and rapid deflation and the beads pop off readily even at less than complete deflation.

    Saying that-

    I can tell you this and I'm repeating myself for clarity. When I first tried it, I too was quite wary of the CT's bead interaction with the rims bead lock/lip. The first CT I mounted had a very pronounced bead protector that gave me fits when trying to mount the tire. I eventually mounted it but I used copious amounts of lube to do it,,,, more on that later. BTW, I've learned a trick that will make the next CT much easier to mount and will require little if any lube.

    The 1st issue that had me being worried that the CT's bead dia. might be larger and that might allow the beads to slide over the rim lip. Nope, not a chance at least on this CT/rim combo. I've mounted alot of tires, more than most, less than some but the gist is,,,,, I am a experienced tire installer on bikes, cars and trucks. I know a good fit when I see, feel and hear one. Hear one you say? Yep, a good, tight fit will lead too a loud "pop" when the beads pop over and into the bead lock valley. I heard two distinct "pops". Better than many MTs I've intalled. I also purposely over inflated the tire to check to see if the beads would catastrophically fly off over the rim lips as some of the worry warts have pontificated to no end. Nope,,,, those beads ain't gonna slide over and fly off the rims causing a catastrophic release of air pressure that would result in kittens maimed, nuns killed and the atmosphere lit a fire.:huh:lol3

    2nd issue,,,, are the CTs beads a "good enough" fit so that in the event that the tire lost air pressure instantly, the beads would stay on the rim well enough to safely get the bike stopped. To test this I used two means, first I simply release all the air pressure and actually rode on the deflated tire. While the CT didn't turn out to be a run flat, the beads didn't pop off in roughly a 1/2 miles of fairly rough and pot-holed dir/gravel road. I leaned heavily at low speeds and purposely hit pot-holes in a "worst case" test of the ability of the beads to stay on the rim. Passed with flying colors. Matter of fact, I think with a modicum of common sense {woefully lacking by some in here}, one could ride for as long as it took to either procure a repair shop or find a good place in which to repair it safely yourself. I have had plenty of flats on bikes,,, sometimes I've had the MTs beads fail before complete deflation, immediately during deflation and I've even run into a couple that just wouldn't pop off at all due to corrosion. I would say the CT did better than most MTs on this test.

    The other thing I did was place a mark on the rim and the tire to check for the rim spinning inside the tire. Remember the remark about "copious amounts of lube"? Even with lots of lube on the tire, too much to tell the truth, the rim didn't spin inside the tire untill I air down to around 10psi. Once again, I did everything I could to get it to fail by repeatedly dropping the clutch hard and fast {read, wheelies!} and by slamming on the rear brake repeatedly. I have no doubt that had I not used so much lube, I could have dropped the tire pressure even lower before the rim started spinning inside the rim. Maybe to the point of zero pressure. I've spun the rim inside the tire on several bikes, mostly when using low pressures and no rim locks. Once again, the CT passed with flying colors and did better than most bike tires in my experience.

    So, the CT's beads didn't slide over the rim when pretty drastically over inflated.

    The beads didn't pop off when the CT was completely deflated and ridden on.

    The rim didn't spin inside the tire untill the air pressure was lowered to 10psi and it was instigated by some very rough treatment in an effort to make it fail. And in the fact that the tire and rim was liberally lubed just before, that 10psi threshold is admirable in my opinion based on my experience.

    So what exactly is the dangerous part again? What's this about there is basically no way the CT's bead will make properly or even "good'nuff" on the motorcycle rim? Yea buddy.:wink:

    Oh, and I'm no engineer but I did stay at a Holiday Inn Express last night. That make ya feel any better.:1drink:rofl

    Seriously though, I do have a skill set and back ground that would greatly benefit me in scientifically based objective testing. Which is exactly what I did, in real world and practical sense. The guy in the link simply pointed out the dissimilarities and didn't even try to investigate whether those dissimilarities would result in actual, real world problems,,,,,,, just potential issues that might lead to problems. He also failed to point out that there can be rather substantial differences in motorcycle rims and tires and for the most part, you rarely have an issue. He simply set out to substantiate the position that a CT is not identical with a motorcycle rim. No problem, I nor most other CT users deny that and I at least have know it since well before I decided to try it. He prove there might be an issue, I and other in the real world have pretty much shown that for the most part {no issues that I've heard of and I've done alot of looking}, those issue simply do not lead to issue in the real world.
  9. randyo

    randyo Long timer

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    fwiw General Altimax Arctic 205/50-17
    [​IMG]
  10. kingby

    kingby Adventurer

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    That poster really didn't fail to do anything (at least in that specific post). He pointed out the differences in design (both the bead dimensions and the forces considered in designing and testing tires by the manufacturer) and presented the information for others. Thats it.

    These differences are present due to the application intended for each product. You have determined (through your homebrew testing and admitted advanced understanding but still limited engineering knowledge) that ct's work good enough for you in a motorcycle application. Are we on the same page still?

    What I would like to bring to other's attention who are contemplating going the ct route is that the manufacturers have done extensive design and testing work to ensure their products meet the requirements of intended applications. They even go so far as to over engineer their tires in certain parameters to try and give some margin of safety for intended use. However, in this discussion the ct's are being subjected to unintended applications. I am not aware of a single car tire manufacturer who has gone through an analysis and testing program with the intention of determining whether a ct is fine for moto use, nor have any endorsed the use of a ct for any moto application. Without further scientific testing (at least in accordance with industry best practices and standards) and endorsement from the manufacturer, people should be careful about what they assume to be ok, because a some anecdotal evidence and homebrew tests presented as such on an internet forum.

    Just because you don't see any issues using the ct on a moto, doesn't mean there aren't any and won't eventually present themselves in a catastrophic manner at some point. So be careful is all I am saying.
  11. amk

    amk Been here awhile

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    Yes, the differences in the rim/bead shapes are obvious. And a ct was designed for different loads, forces, momentums that it experiences in an mc application. However, experience is the only criteria for what the truth is. And according to our experience we have not heard of a single case of a catastrophic failure, or even of a minor one. I am sure, putted on a race bike on a race event it will be dismounted in a sharp turn and a rider would die, but we are not racers. Even if we think we are, in reality we move slowly, we turn badly, we obey, sometimes, for speed limits, and for those speed limits, or slightly above them, a ct works.
    Anyway, the only problem I have is a lack of current information of what works, what not width wise. I put my General UHP Exclaim 205/55-17 on the season before last. And it was on sale that time, because general was discontinuing it. Now it is impossible to find. The main question is will a tire clear the drive chain? My UHP and others cleared it with a scary to think of 3-4 mm gap. And now I hear stories some new tires do not clear it at all. Does anybody know what tire of the current generation works on the 2004-2011 Wee?
  12. LexLeroy

    LexLeroy Whiskey Tango Foxtrot Supporter

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    Do a search for "darkside" on the Stromtrooper.com site - lotsa' VStrom-specific posts. You can also go to Tirerack.com and use the "shop for tires by size" feature. Tire Rack lists tire diameters, section widths and tread widths - all good things to know when you're looking for likely candidates.
  13. corndog67

    corndog67 Banned

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    All I can think of when I read about putting car tires on a motorcycle and running 20psi or less so they have some squish to them, is that some people really don't have much common sense, but I guess since nobody has been known to have died yet from it, it must be cool.

    I'm really wondering what the tireanufacturers, and the bike manufacturers have to say about it. If they both recommend against it (which I would assume is the case, but I could be wrong), why would someone do it anyway?
  14. the_sandman_454

    the_sandman_454 Been here awhile

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    They're obviously going to recommend against it. It is a CYA thing. They haven't tested it, so they're not going to say it is ok. That doesn't automatically mean is isn't safe, just that you're venturing into uncharted (officially) waters. It looks like there is a bunch of anecdotal evidence where people are using these and not having issues.

    I think it is a fascinating idea, and in cold weather or where there's a risk of snow or ice, a General Altimax Arctic would probably be awesome on there (these tires rock as snow tires on the cage).

    It is interesting though to think about the pioneers of anything. People were quick to say don't do that, terrible idea, unsafe, etc. If the pioneers had listened to the naysayers, we wouldn't have anything we have today. I think I approve of the project as long as folks go about it a bit cautiously (at least until they see what works/doesn't).
  15. amk

    amk Been here awhile

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    If you read the thread you advised you would find all tires mentioned there are obsolete. It is an old thread.
    Measured width on tire rack provides some info, but not enough, generally because it is measured on a standard car rim, moto rim is much narrower, tire is pinched much more, becomes narrower, but will it clear? Besides that width is rarely available,definitely not for all tires listed there. That is why I was asking for a personal experience rather than common sense/general advise.
  16. Hoppalong

    Hoppalong Adventurer

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    That can't even reach the level of even a silly stereotype.

    A poorly informed person putting car tires on a motorcycle is a "pioneer"?

    We "wouldn't have anything we have today" unless there were people dumb enough to put car tires on a motorcycle?
  17. Jud

    Jud Long timer

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    I think we actually started on the same page as I specifically mentioned-
    Which is basically what you said here-
    The gist is the same in my eyes.

    The reason I mentioned "failed" was because he did fail to point out that there was in fact, a good bit of variation in MT, MT rims, CTs and CT rims. So in fact, one MT rim might well be quite a bit different than another and the same with the tire's beads,,,, especially between different manufacturers. Considering the information in his research and post, I think he is well aware of these issues and failed to mention them. To a casual reader that might not be aware of these variables,,,,, that would be a major piece of information that could easily color one's perception and opinion of this practice.

    In his illustration of the CT on the MT rim, the drawing was as if the bead was in the relaxed state, as if the tire was made of something hard that would not conform. In the cut away pics, the same thing, the bead was just placed next to the rim in a relaxed stated. The fact is that the rubber conforms in some amount when first,,,,, forced onto the rim's bead lip and secondly, when air pressure is applied.

    Again, the casual reader scanning through his post/research might well come away thinking that the CT's bead will always remain as depicted in his illustration and in the cut-way. In this, "I" {my opinion} think he failed to tell the whole story because as I said, we know for a fact the rubber beads will deflect, deform, conform "whatever term you choose" to the rim's bead lip. To what extent,,,, that's open to speculation and or conjecture. I will say that I did inspect the bead area of the CT and it appeared to me that it did completely conform into the MT rim's bead. Real world testing would seem to substantiate that also considering how well the CT's bead stayed "beaded up" on the MT rim even when deflated.

    Failure to include those two points could easily color the opinion of someone that isn't fully aware of those points. Failure to present all relevant information can and will color opinions based on incomplete data.

    I think almost every darksider in this thread knows there are differences in motorcycle and car tire bead and rim bead dimensions. I would think almost anyone that just took the time to look at the two can figure that out. The information contained in the link isn't something that I think most of us didn't know. It did go into great detail and at times, bordered on being too detailed as if there was almost a point made to intentionally muddle the waters enough so a layman would just decide it was too complicated to even attempt to understand and rather than try to safely figure out,,,,, simply continue with the accepted norm.

    Just like running a front motorcycle tire from one manufacturer and a rear motorcycle tire from another "might" present unforeseen issues, running a CT "might" also. One can not foresee any and every imaginable scenerio and no manufacturer will ever make a blanket endorsement of the unknown. But that doesn't mean it will not work and in some cases, work damned well.

    I don't think any darksider in this thread has said that one shouldn't ignore the fact that this is steeping into the unknown and and that you should do it with eyes wide open. For the ump tenth time,,,, we know there are indeed differences. We are not lemming, running to the cliff edge without any thought or care simply because the others are. But honestly there are alot of lemmings in this thread that simply refuse to believe that this will work and work quite well in certain applications and for all intents and purposes,,,, has been done successfully and safely over and over in the real world.

    I do appreciate your concern as I think it's an honest and legit concern and you are trying to present the "better safe than sorry" point of view. But please remember, if we all took that "better safe than sorry" view,,,, many of us wouldn't even be riding in the first place much less the sorta riding many of us do because riding is inherently "less safe" that driving around in some 2 ton Volvo at strictly legal speeds surrounded by crumple zones, air bags and seat belts with ABS, Stability Control and Traction Control nannys.

    I also appreciate your views and your refreashing lack of ridicule. Sometimes, I have to admit that at times, I do get my ass on my shoulders because of constant simple minded attacks and will include plenty of sarcasm. I hope I am conveying my position in the same professional manner as you are. :1drink
  18. PeterW

    PeterW Long timer

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    Not a winner, Harley-Davidson already have THAT market sewn up.

    Pete
  19. the_sandman_454

    the_sandman_454 Been here awhile

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    Every single invention, new use for an item, or experimentally substituting a different item has surely been met with negative opinions. That's dangerous, don't do that, never use item x to do y or z tasks, that could be bad, etc. Sometimes it works, sometimes it does not. This one appears to work at least reasonably well.

    Things get repurposed every day for uses which they weren't originally designed. Like milk crate/KLR combination. :lol3. Granted, some repurposing of items is safer than others.

    By definition, anybody who tries something new is pretty much a pioneer in that particular field. I'm guessing the first caveman who invented the wheel faced naysayers too. The bottom line is that we would have nothing if someone hadn't thought to himself "they say we can't do this, so we better not".
  20. PhilB

    PhilB Long timer

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    :lol3 I love this line of "logic".

    a) They laugh at geniuses and innovators.
    b) They are laughing at me.
    Therefore:
    c) I am a genius innovator.

    Here's the thing: when naysayers naysay, they are almost always right, especially if they have expertise in the field and those they are naysaying to don't. There are very rare occasions where they are wrong and are overlooking something real, but those are by far the exception, not the rule.

    IOW, having naysayers does not in any way provide any evidence that you are right about anything.

    Rock on.

    PhilB