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. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks
    I've not done any durameter testing but I don't think even that would be conclusive because there are other variables and you have to take all those variable into account. My assertion of increased traction with a CT is from 1st hand experience.

    I really didn't notice it at 1st simply because as I have repeatedly said,,,,, I was somewhat skepticle of the CT on the back of a bike myself. I just had the curiousity and huevos to try it. After awhile, I gradually pushed the limits untill I was more worried about pushing the front 705 than sliding the rear CT. During that time, I became very rough on the throttle and with the rear brake. When I removed the CT and went back to a 705 {cause I have alot of takes offs, spares} I had to tone done that which I had gotten used to while the CT was on back. On a couple of occasions I nearly found myself on the ground because I had gotten so used to snapping the throttle wide open coming off a hard right or left. With the CT, it would just grab and wheelie from a fairly heeled over position. With the 705, it actually spun and stepped out a time or two. And yes, you have to grab alot of throttle combined with alot of lean angle to get a turd of a DL650 to spin the rear.

    Same with the back tire. I had gotten so used to the extra traction a CT offered, I started using the back brake more. Not only in straight line braking but when trail braking a smidge in corners or when purposely getting the rear to step out off tarmac. It simply took more brake prssure to get the rear to lock up in those instances and I didn't notice it untill I swapped back to the 705.

    Nearly everyone that has tried a CT has experienced the same thing, even the ones that decided they didn't like it for what-ever reason.
  2. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks

    I really wish you could ride with him. He is far from wrong and I'll tell you right now, he is a better all-around rider than the great majority of people I know. Way better.

    Again, you are basing your opinions and thoughs on non-existant data. You shouldn't make assuptions feller.:1drink
  3. joexr

    joexr Banned

    Joined:
    Jan 4, 2011
    Oddometer:
    5,022
    Years ago bikes may have used car tires , total loss ignitions and lubrication systems then technology improved. That's why there are separate bike and car tires today. If anybody was going to be a proponent for old tech don't you think it would be Hardley? But even they and their time-lost customers use MOTORCYCLE tires.
  4. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks
    I think you are reading too much into our sarcasm or our ridicule of some rider's skill. Riders that might well be quite busy ridiculing our skills.:lol3

    I do appreciate your "live and let live" mentality and honestly, that's our take on it. Sometimes it's easy to get caught up in the BS.
  5. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks
    Like I said, I hope we can meet up one day and go for a ride. Maybe Bluelighting can show up too.:1drink
  6. mrphotoman

    mrphotoman Long timer

    Joined:
    Feb 20, 2011
    Oddometer:
    1,689
    Location:
    KBR27
    snow tires properly inflated and mounted on a car feels like you are driving on marshmallows and handles like shit. I could only imagine how wonderful it handles when under inflated on a undersized rim on a motorcycle lmao :rofl:rofl:rofl:rofl:rofl:rofl:rofl:rofl:rofl:rofl
  7. kingby

    kingby Adventurer

    Joined:
    Feb 5, 2013
    Oddometer:
    92
    Location:
    The Rock
    Well... theoretically the "size" of the footprint has nothing to do with traction. Admitted, under real world conditions, tire load sensitive comes into play and at higher vertical forces a larger footprint has a more linear friction response (for instance...helps in lateral grip/slip angle in upright car tires... turning a car), but under normal moto conditions, traction is simply a function of the coefficient of friction (rubber compound and roughness of the road surface) and the force applied between the two surfaces (bike weight and load transfer fore and aft due to accel/deceleration). Contact patch area has a very limited effect (some tire load sensitivity) in the real world model for the moto case and is not even a parameter in the theoretical calculation.

    There are other reasons for larger footprints as well (heat management and stability being the big ones... note that autos generally keep a consistent footprint due the generally upright nature of the tire and the larger footprint helps stability there... motos on moto tires generally keep a consistent footprint due to tire profile through lean angle and a larger footprint can help with stability there... but motos on CT's seem to have an abruptly altering footprint and a wider tire actually can promote a larger shift in contact patch area/pressure distribution during a lean, which hurts stability even if the contact patch is larger).

    In fact, depending on the tire pressures used, the flexibility of the side wall and the height of the side wall, a wider tire footprint may actually put down a smaller contact patch as shown here:

    [​IMG][​IMG]

    Therefore without a more methodical analysis of what tires, at what pressures are being used on which bikes, its really a crap shoot between rubber compound, vertical applied force between the road and tires and the role tire load sensitivity plays in the traction equation (sidewall flexibility/sidewall height/tire width/pressure dependancies).

    That is why the moto companies and the tire companies put in the hours of testing and analysis. They are trying to offer some consistency (and in return I would argue level of safety that comes with that known quantity of consistency) to the consumer with approved tire combinations and consistent recommended tire pressures.

    Not that I am against experimentation, but making blanket claims that CT's work consistently well in your applications may not actually be true. I think everyone doing this experimentation should be aware of these variables (hopefully with some better info, make better choices to improve the tire performance). Looking at the complexity involved, it would be a very difficult and long process (or you just picked the lucky CT) to actually consistently find a CT that works similarly every time. I am not even going to get into the psycho-perception tricks that our brains play on us trying to convey the changes with our butt dyno's. All I am going to say is that we can convince ourselves of anything if we believe it.

    The ability of one tire to grip harder than another tire comes mainly down to coefficient of friction of the rubber compound. That why I asked. With the claim of better traction, I was wondering if there was a specific compound or load rating being sought. My experience is that Moto tires have significantly stickier rubber (at the cost of tread life) than auto tires.
  8. Hoppalong

    Hoppalong Adventurer

    Joined:
    Feb 17, 2012
    Oddometer:
    64
    Location:
    Sierras
    Not likely. I'd be afraid to ride anywhere near you guys. You're on motorcycles with _car_ tires, fer chrissakes.

    Reminds me of the movie 'Dumb and Dumber'.
  9. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks
    Theoretically ehh? I never see drag cars and bikes purposely go down in tire contact patch {I say patch because height, and construction can have an effect just as width} when having issues with traction. I've seen people go down in patch size {either width or height} when they had the traction they needed and wanted to lose some rotating weight.

    In autoX, you don't generally see people go down in contact patch to gain traction. I've seen some do it because the trade off of lighter weight or more balanced handling would offset the decreased traction.

    Same with road racing.

    Now bikes. I used to road race and I've done my share of trackdays. All things equal {same basic bike, set-up, tire construction}, I've never seen someone mount a 160 in place of a 180 or a 190, even for a qualifying lap where longevity isn't an issue.

    Yes, you can even get too much contact patch and lose traction {seen it in rock crawlingwhere the contact patch got so large compared to the weight that there wasn't enough pressure {psi} exerted. That pretty rare though and more often than not, one of the 1st means to gain traction, leading to better times, lap times or the ability to travel rougher terrian is to add contact patch. Otherwise, we would be seeing 1199s running 130s to save rotating and unsprung mass. And no, Ducati isn't running a big fat rear tire just for edurance racing where longevity might be an issue.

    Theory might well say that you can take one tire, and keep all the variables the same except width, take 6 inches from that width and have the same traction but man, in real life,,,,,,,,, it don't work.

    Making blanket claims that a CT works in our application seems to be "more true" {works well} than the ones adamantly stating it will not work, can't work and only an idiot would debate otherwise. The only people saying these this are the ones that have not and will not even try it. The ones that have tried a CT are saying that witt-in certain applications, the CT can have merit and will work,,,,, but with some drawbacks. Drawbacks that may or may not make it a viable option for everone.

    As for the psychology of sugar pills,,,,, like I said, I used to race and I raced alot of different vehicles and classes. Through dynoing, runs and laps, I discovered that the butt-dyno can and will lie. I also learned that alot of things that are "suppposed" to work either do not or they are insignificant. I more than most am very skeptical of "improvements" and have been quite aggravated when something that I thought was going to result in better times,,,,, just didn't pan out in real life.

    I will repeat, the CT isn't a cure all or the Holy Grail of motorcycledom {in spite of some of the naysayers in here trying to attribute that to us}. We are saying that in certain application the CT works as well and even better than other MT options when all things are considered. Again, you would not run a Pilot Race on a Goldwing even if you could, you would not run a ME880 on a GSXR or a TE510. We are runnung a CT on a DL650 because the trade offs of less sharp handling at the extremes of tarmace and off-tarmac, more unsprung and rotating mass, at times, odd handling, ect. of running a CT simply are not much of an issue as compared to the benefits of running a CT - drastically better wear, additional durability, more traction wet and dry on tarmac, straight up and cornering and in most off tarmac conditions.

    The naysayers say there is no way it has more traction. Everyone that has tried a CT disputes that.

    The naysayers say it's dangerous and pontificate on and on about the beads not being compatable and that this will result in catastrophic failure,,,, hasn't happened yet that anyone can use as an example. To the contrary, the people that have tried it usually say the tire bead to rim bead fit is tighter. That would actually be "more safe" in the event of a sudden lose of air pressure.

    The naysayers says it handles like crap,,,, well,,,, that's depending, some that have actually tried a CT and decided they didn't like the handling and went back. "Handling" is a pretty subjective thing and I will not tell someone what their idea of "handling" should be. If they don't like the way a CT feels, cool beans. I ain't for them no matter what benefits they might see. Many of the people that talk on and on about the virtues of "handling" are riding "less than a sportbike" and are actually riding pretty slow in the corners so even though they think they might need the latest and greatest sticky name brand rubber,,,,, they could actually be just fine on some POS {in their mind} tire, even a CT.
  10. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks

    Sorta the standard answer I've noticed.:1drink
  11. kingby

    kingby Adventurer

    Joined:
    Feb 5, 2013
    Oddometer:
    92
    Location:
    The Rock
    So is all that directed at me? I am simply trying to have a factual discussion and get to the real reasons CT's either are or aren't any type of advantage. (Also, while you were posting, I clarified a small section of my response, but it did not change any of my meaning)
  12. Daddyo

    Daddyo Been here awhile

    Joined:
    Dec 17, 2010
    Oddometer:
    183


    Yea I probably am : )

    DO
  13. BlueLghtning

    BlueLghtning Riding is my passion

    Joined:
    Feb 16, 2004
    Oddometer:
    6,238
    Location:
    Peachtree City, GA and Full Time RV Travel
    Good technical data there. I think you and Jud have more background there than me.

    I pretty much agree with Jud though about seat of the pants riding. It doesn't always make sense, but you could be a lot more sloppy or aggressive with a CT without worrying about it spinning or slipping out on you. It was very predictable too if you started pushing past the limits.

    I went back to 705's myself around last Sept specifically for a trip to WV where I knew we were going after curvy roads and I was riding with 3 other riders that were about the same or better than me and 2 of them on sport bikes and all 3 of them on bikes more powerful than my DL650. I had a few moments early on where I was pushing the 705's too much coming out of turns and had a few pucker moments. I had to readjust my throttle hand to be a bit smoother as I had gotten lazy with the CT and so used to just ham fisting the throttle coming out of turns.

    BTW, Jud brought up ME880's. I've never ran them, but they have a reputation for being long lasting tires. I think you generally find them more focused in sizes for cruisers, but they do happen to come in large Adventure bike sizes too. I don't think anyone would say they would be a tire of choice for mountain riding and twist roads. However, we had a guy on a Tiger 955i that was running a front ME880. He was doing decent with it until we hit rain and wet roads. What a crappy tire in the rain and wet pavement that tire turned out to be. He's a good rider, but I had never seen a tire slow him down so much and scare the crap out of him so many times. I think he promptly took that tire off once he got back home. Bad thing was we ended up with 2-3 days of rain and wet pavement, so it really sucked to be running that tire. I thought to myself when he was having all that trouble that I could have been running a CT and enjoying myself more than he was with an actual MC tire that just absolutely sucked on the wet roads.
  14. DAKEZ

    DAKEZ Long timer

    Joined:
    Mar 18, 2007
    Oddometer:
    19,888
    Location:
    Begin Op Zoom
    Dumbsiders of the World unite!

    When I wear out the tires on Frank I am going to replace them with Car Tires! Front and Rear... and SIDE! :1drink
  15. randyo

    randyo Long timer

    Joined:
    Nov 17, 2007
    Oddometer:
    2,581
    Location:
    Northern NewEngland
    I'm running a winter that doesn't need to be warmed up to have traction on pavement, even in below zero F temps, it has sipes and it flexes, it grips on snow and on ice, and pavment,show me a MT that does that, show me a motorcycle tire that even pretends to do that
  16. randyo

    randyo Long timer

    Joined:
    Nov 17, 2007
    Oddometer:
    2,581
    Location:
    Northern NewEngland
    Agreed, single track on a car tire SUCKS, maybe more with a winter tire, the width catches every single imperfection in the track, even with a good suspension it sucks (my rear shock is a WP) maintaned gravel roads, the winter CT is the balls, the front tire is the real limitation

    One thing I really had to get used to taking off from a stop in loose material is how the tire hooks up and gets you moving while with a MT, you get wheelspin before you start moving

    another thing I dislike about the CT is the radial tire flex you feel when your manuvering your bike around walking beside it

    I don't mind limiting my single track riding, its a 500lb beast to begin with
  17. Chip Seal

    Chip Seal Long timer Supporter

    Joined:
    Aug 18, 2004
    Oddometer:
    3,139
    Location:
    Western Orygun
    Reading this thread is like listening to folks that believe the bible literally. God wrote it. I read it. I believe it.

    I agree with an earlier poster. All the "Darksiders" are justifying car tire use with bullshit. They just write paragraphs and paragraphs of nonsense to justify being a cheap fuck. "Pioneers" WTF! Dumb cheap fucks is what I call them.

    Using their logic, a studded snow tire should eat up single track and gravel roads. Has anyone tried doing the TAT on a studded snow tire. Oh right, they don't make one skinny enough to fit your KLR?

    I hope the hell a Darksider doesn't get his ass sued off when he slides on rain slicked road causing a multicar pile up.
    Your insurance company is going to find a way to wiggle out of paying that claim.
  18. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks
    I think the bible thing you mentioned this is actually the other way around. Religious people believe in something they can't literally prove. They believe based on "faith" and many, simply what their "experts" tell them because if they don't they will go to hell. Better safe han sorr which is exacl what some of you are saying. Better to not try it because of the "what if's" than to simply take the time to literally "prove it" one way or the other.

    We are are if anything, agnostic in our thinking. We don't know if it's true or not but rather than blindly follow the lead of the "experts" that tell us what to believe and how to believe, we challenge convention and just tryit. Once we try, we find out that it does work, some find it works great for them, much to the chagrin of the experts that tell us that hellfire and brimstone will surely follow. Some decide that after trying it, it ain't for them but they still prove to themselves that it does work and there is in fact,,,,, no hellfire and brimstone coming simply because you choose not to believe everything that gets shove down your throat by people that get downright angry if you don't do what they say.

    BTW,,, why do you get so bent that you need to talk outta your ass about something that you have absolutely no knowledge. :deal

    Maybe you and mrdumbassman can start a new religion.:rofl
  19. Chip Seal

    Chip Seal Long timer Supporter

    Joined:
    Aug 18, 2004
    Oddometer:
    3,139
    Location:
    Western Orygun

    I rest my case!:lol3
  20. Jud

    Jud Long timer

    Joined:
    Dec 22, 2007
    Oddometer:
    3,930
    Location:
    Arkansas Ozarks
    You sure did,,,,, brother Chip Seal.:pope