tire pressure?

[crashtd]

usually when i go to the trackday, i ask the tire guru to recommend a psi setting for my treads, but for the life of me...i couldn't tell you the theory behind the number he comes up with.

can someone enlighten me on the factors they weigh when pumping up before a trackday? :O on the street i pretty much have my golden setup, but man on the track its a different can of worms :banghead

-:banana

[tanuki]

I know what you mean - does seem a bit random, and if they have 2 tyre monkeys you can ask them both and get slightly different answers...think its down to feeling for how warm the air and track are likely to get based on weather and sunshine...

[TarkMalbot]

You tend to let the pressure down a few PSI on the track to get more tread onto the track for more grip and less chance of spinning up. This makes the tyre warm up quicker. And with a hot air in the tyre the air particles expand creating a higher pressure. This usually makes your pressure go up about 3-5 PSI. I measure my pressures first thing in the morning before I put the tyre warmers on. Then when they are hot they are usualy about 2 PSI higher.

Its usually about 28 in the rear and 30 in the front for most tyres on my IL4 600 and 1000 although I did run 27/92 with Bridgestones. Not sure what I would run on the RSVR.