Can anyone tell me what "science" is involved with correctly setting tire pressure on the track? I realize that the pressure increases throughout the sessions because the tires heat the air inside, it expands, etc, etc. However, how do decide what to initially set it at? Car in question is a '96 A4q, no real mods (performance or anything else) to change weight, speed, etc except the installation of the Audi A4 sport suspension. I'm driving at Lime Rock in CT in 2 weeks, so figure a high temp in the almost 90's during the day, a low of abou50-60 during the first early morning sessions.<p>Thanks!!!<p>Jon<br>'96 A4qs

Anyone who tells you that they have the definative answer is full of crap. You will need to raise the pressures, but how much depends on:<p>Your driving style.<br>Your mean velocity, divided by the track coefficient of friction, multiplied by the national debt of Argentina.<br>Your tires, and how much you like them.<br>Your instructor, and how much you scare him.<p>I'd raise them all about 3-4 lbs., and then see how far you're rolling over the edge of the tread. Raise them too far, and you'll provoke the anger of the Handling Godz. If the car feels like it wants to oversteer, lower the back pressures 2-3 lbs. at a whack, until goes away. <p>Once you find a front/rear pressure ratio that has handling characteristics that you're comfortable with, try and maintain that ratio as you adjust all pressure up and down.<p>If you're unsure as to what you are seeing when looking at the wear patterns on the tires, ask someone EXPERIENCED...not just some jamoke parked next to you in the paddock. Everyone thinks they're an expert. Ha.<p>John<br>Trained Seals Racing<br>(the only expert I trust)