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My tyres were under pressure.

pbassredpbassred Posts: 208
edited March 2016 in Commuting general
My commute is only 2 miles or so. I dropped it on the ice the other day. Took a ride along a paved path yesterday. Each time I hit that moist churned up leaf mold it all went a bit skittish! The same with wet road gravel this morning. I'm riding a stock(ish) Trek DS8.3 with 38mm Bontrager LT3s on. It felt a little hard, so I thought that maybe I should let a little air out to get more grip. I checked them first:- 45PSI :? So I put another 15 PSI in which is still low (according to some calculators).

Is it possible to LOOSE grip with under inflated tires?


  • kajjalkajjal Posts: 3,380
    Yes, if low enough the tyres deform when under force such as going round corners or heavy braking.
  • 45psi for 700x38mm tyres isn't that low to be honest, folks run CX clinchers lower than that, it is a fairly cheap and heavy tyre with a fairly hard rubber compound and tread for hardback, leaf mold is fairly slippery for more expensive tyres with soft compounds and full nobs tread tread.

    If the psi is suffently low that the side wall is bulging massively and folding under load, but if so the tyre should feel and look terrible as it squirms.
  • The RookieThe Rookie Posts: 27,811
    Low pressure won't make it feel skittish, that's just a lack of grip, bearing in mind that leaf mould when rotten 9as it probably is now) is a better lubricant than many commercially available greases......
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • mr_eddymr_eddy Posts: 830
    Silly question are you hitting these areas dead straight ? If you are cornering even slightly when going over wet leaves / Ice / Gravel etc then depending on your speed you could be washing out your wheel in other words its trying to skip out away from you.

    This could be exacerbated with low pressure. Personally I have always found that getting my tyres to about 80% of the max pressure (listed on the side of the tyre) keeps them firm enough to avoid deformation but also pliable enough to soak up some road bumps.
  • pbassredpbassred Posts: 208
    Thanks everyone. I have changed types to the Marathon plus tour. They are really hard although a friend of mine reckons that they soften up after a few hundred Km. I had them at 60. They ping stones out rather than going over and they had a few sideways skips. I took 10psi out and they are worse! I recon they are squirming, so I will be going up again.
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