Tire pressure for autocrossing with V710
05-23-2008, 01:05 AM
#2
Instructor
Member Since: Apr 2006
Location: Lancaster Pennsylvania
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It kind of depends on how competitive you are and or want to be. I tend to take it way too serious and love data but here's a little info without sharing to many secrets. There lots to think about. Temps. Is the surface cold or hot. Is the course long and open or short with tight sharp corners. What's your driving style like and how fast to you drive. Not to mention the setup of the car. Basically, I usually don't run more than 40 psi in the front (although you can) but usually less and always less in the rear. I have run as little as 2lb differential to as much as 8lb in the rear. It all depends on the condition. Keep notes, make big changes and note the results and you should be able to narrow it down and know exactly what it takes for your car, your style and course. Good Luck.
05-23-2008, 06:59 AM
#3
Drifting
there are lots of factors but one of the better ways to dial them in is to get your hands on a pyrometer and stick that in the tires after each run to makes sure the temperatures across the tread are all about the same and in the range the tire manufacturer recommends. i was running 315/35R17F and 335/35R17R last season and used 26 psi front and 22 psi rear and the temps looked good every time i took them. 
05-23-2008, 08:08 AM
#4
Racer
Member Since: Jun 2004
Location: Reinholds PA
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For an autox your tires are not going to heat up as fast as a HPDE day, where your out for 20 mins. at a time. So I tend to start at about a 4-5 psi spread - front higher than back. I normally want the fronts to be about 36-38 psi hot. You should expect about a 5-6 psi increase from cold to hot. So cold starting pressures may be something like 32/28.
At an HPDE your pressures can jump 12 psi.
At an HPDE your pressures can jump 12 psi.
05-23-2008, 11:10 AM
#6
Pro
Member Since: Jan 2007
Location: Albuquerque NM
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As for temps I don't know as I've never had a probe in them when they were prime and when they were over or under heated. Sadly I go by the temps I feel on my hand and elect to spray them with water or not based on that and how they felt the previous run.