Strange track day tyre wear....

Discussion in 'Trackdays' started by navvy10, May 9, 2013.

  1. navvy10

    navvy10 Well-Known Member

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    Not sure if anyone has seen anything like this but this is how my friends brand new bsb tyre looked after a day at Snetty on his 600.

    Looks like tearing?? image.jpg
     
  2. Remal

    Remal It's ME
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    Could be cold taring from the looks of it. pushing to much on cold tyres. did he use tyre warmers?
     
  3. navvy10

    navvy10 Well-Known Member

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    Yes mate he did so it's possibly too much air pressure or suspension issues??
     
  4. samd1985

    samd1985 Active Member

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    I'd second the cold tearing as its quite deep. If it was hot tearing it would tend to curve in towards the centre of the tyre due to centrifugal force, and be shallower.

    Too much air pressure is the likely culprit. It could be out by only 1 or 2 psi, so not by much but it's enough to cause that tearing
     
  5. navvy10

    navvy10 Well-Known Member

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    This was a fast session where the tyres were very warm so unlikely to be cold tears but the air pressure may just be the culprit!

    Thanks for the feedback guys ;)
     
  6. samd1985

    samd1985 Active Member

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    Cold tear is not quite what you'd think... Its in fact due to localised excessive heat build up.

    It happens when the contact patch is too small (due to the high air pressure) and basically the area overheats and melts away. With slightly lower pressures the contact patch becomes larger and spreads the load, and ultimately heat, across a bigger area. Then, once the pressure goes the other way too much, I.e. too low, the carcass overheats due to too much flex and friction, resulting in hot tear
     
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  7. Jollygiant

    Jollygiant Member

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    Exactly what I just got at brands.
    Will have to change my tyre pressures for now as my suspension needs servicing.

    image.jpg
     
  8. samd1985

    samd1985 Active Member

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    Again that looks like cold tear with an added rebound problem due to the fact the wear increases and decreases as it moves around the radius of the tyre.

    Also worth noting that while tyre pressures are most likely the issue, if after having sought advice from say the tyre guy at the track and your pressures are set correctly, if the wear still remains then you need to look at suspension settings. First thing to check is rear sag. Free sag should be around 5-10mm (that's the difference between fully extended and the sag created by the bike's self weight). Rider sag should be around 25-30mm for track. If not, adjust the preload until they are within that range. If these figures are in the ballpark then move onto compression and rebound - you probably need to soften them up a tad so the suspension does most of the work rather than the tyre.

    There's plenty of how-to guides around on the net and YouTube too.

    Hope that helps.
     
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  9. Jollygiant

    Jollygiant Member

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    My suspensions knackered anyway. All the settings are to max. Going to get it devices and prob better springs in
     
  10. Stimo

    Stimo Member

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  11. navvy10

    navvy10 Well-Known Member

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  12. Stimo

    Stimo Member

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    no problem :)
    have the page book marked for easy looking :)
     
  13. Haggler ®™

    Haggler ®™ Active Member

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    I,m NO expert but I know Snetterton (I live 30 miles away) and I always use Racetecs at 26 rear presure on a warm track........justmy2penceworth.
     

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