Debate and quest for knowledge for track tyre pressure. - I put this in general forum as this can also effect fast road riding. I know riders who only ride on the road who put warmers on before a Sunday jaunt... Conversation down the pub debating the following: Years ago tyre pressure were quoted at cold temp; they are now more often at the track quoted as hot temp, or on warmers temp. I understand this methodology... I like to check the pressure as soon as I get into the garage after first session. Correct tyre setup is a balance of pressure and heat: Adjust the pressure to get the right heat... If tyre is going like chewing gum; then it's too hot... yep; get that... Bit I don't get... If the tyre is too hot; then to make it run cooler do we add or remove pressure? It seems to be the case that on a hot day we run lower the cold pressures, to get the correct hot running temp - pressure. This is the bit for the pub debate. My thought is that a lower pressure will cause more tyre flex; and therefore more heat. Therefore: the question is: On a hot day do we want to run them a bit harder to create less flex and therefore less flex generated heat... Or run them lower as track temp will increase the tyre heat and therefore pressure?? So, for example. If it looks like my tyres are getting too hot, do I put more air in; or take it out. But more importantly please, why?? Very keen on getting to understand the physics of it all... Cheers, Bob
Actually Charlie Boyle, I think. But anyway... adding my ill informed two penn'orth before the more knowledgeable chime in .... I think you have a decent handle on the physics already. It just needs a little tidying up. The way I see it, the baseline is that the ambient air/track temps will have their effect anyway at both high and low tyre pressures, but there will be an additional temp rise in the tyre as a result of the flex and this will be greater at lower pressures. Both of these factors would point to, warmer day = lower pressures. But, just to emphasise, the above is deduced by reasoning rather than learned by experience.
