tyre pressures

[Shifu]

The advice I have recieved for track riding is to drop the pressure by 3-5psi. The logic is a) That you want a bit more deformation of the rubber for better grip and b) that you run the tyres much hotter on a track day so the pressure increases.

I run 42 F/R and notice the difference if it drops under 40.

The lower pressures increase the size of the contact patch and that influences only your tyre wear (and can affect handling in the extremes). There is no more grip as it is independent of the area that is contacting the asphalt. For the track the main concern should be a tyre temperature (as it affects the traction) that the given pressure produces. The lowewr the pressure the more flex in the tyre and more heat gets generated. Optimum temperature will vary between brands but generally 70 - 90 deg C. So the correct pressure is the one that gets your tyres to that temperature and keeps it here without overheating for a given riding conditions track, ambient temperatures etc. For the normal street riding normally there is no need to complicate it that much and is OK to stick to recommended pressures from TYRE MANUFACTURERS. I run 38 rear and 32 front on my Busa all the time. Having a good quality pressure gauge is massively important.