Tire pressures during track event
Thread Starter
Straight to Video
Rennlist Member
Rennlist Member
Joined: Jan 2004
Posts: 3,599
Likes: 0
From: Los Gatos, CA
Tire pressures during track event
Hola,
Doing my second track event at Thunderhill next week and was curious what are good psi values for front and rears.
During a few hours of spirited driving I am usually at 40psi rear and 34psi front.
But last time I was on the track the rears got up to 46 psi, way too high. It would also be nice to know how much I should deflate the tires before I start warming them up so I don't have to make a pit stop later when they are hot.
Thanks for any info!
ps. thanks RonCT I know we double post sometimes over at 6speed, just looking for more numbers!
Doing my second track event at Thunderhill next week and was curious what are good psi values for front and rears.
During a few hours of spirited driving I am usually at 40psi rear and 34psi front.
But last time I was on the track the rears got up to 46 psi, way too high. It would also be nice to know how much I should deflate the tires before I start warming them up so I don't have to make a pit stop later when they are hot.
Thanks for any info!
ps. thanks RonCT I know we double post sometimes over at 6speed, just looking for more numbers!
Race Director
Joined: Oct 2004
Posts: 11,202
Likes: 242
From: Ottawa, Canada
46 WAY too hot (for MPS2s). My tires get slippy slidy at that pressure.
38-40 is where you want to be with equal pressures all around.
When it is super hot (like July/Aug) tire pressure will increase 8 lbs. from cold. When cooler a bit less.
I usually start at 32-34 and adjust as the day goes on.
38-40 is where you want to be with equal pressures all around.
When it is super hot (like July/Aug) tire pressure will increase 8 lbs. from cold. When cooler a bit less.
I usually start at 32-34 and adjust as the day goes on.
Racer
Joined: Oct 2006
Posts: 371
Likes: 5
From: San Diego, CA
Huh. On a very abrasive track this last weekend - my first 997 autocross - I ran really high pressures in the OEM PS2s, both to protect the outside edges and based on the pyrometer readings I got. I ran 42-43.5 hot front, and 48 hot rear. That was as high as I wanted to go and I bled air to keep the tires at those levels. Even at those pressures, I had these results: outer edge of the front outside tire was getting excessive wear and was running much hotter than the inside or the middle of the tire; the centers of both rear tires were cooler than the inside and outside; and the front inside tire had pretty even temps all the way across. So, for that lot, on that day, for this driver, pressures in the low-upper 40's were appropriate.
My camber was max negative on the front (1.3 deg.) and -2.5 deg. in the back.
On a smooth high speed track where a person isn't driving 10/10ths, I think significantly lower pressures could be better.
My camber was max negative on the front (1.3 deg.) and -2.5 deg. in the back.
On a smooth high speed track where a person isn't driving 10/10ths, I think significantly lower pressures could be better.
Poseur
Rennlist Member
Rennlist Member
Joined: Nov 2005
Posts: 17,743
Likes: 294
From: Santa Barbara, CA
The best thing you can do is to measure your tire temperatures. Measure each one at the center of the tread area, on the inside portion of the tread. and the outside. (Write them down consistently).
The temperatures of the tires tell you a lot about what you're doing,--scrubbing, over steering, understeering, etc. One of the most secret things in racing is a guys tire pressures. It's like asking a Geisha to open her kimona...
The temperatures of the tires tell you a lot about what you're doing,--scrubbing, over steering, understeering, etc. One of the most secret things in racing is a guys tire pressures. It's like asking a Geisha to open her kimona...
Trending Topics
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Porsche's Top 5 Most Questionable Naming Decisions
Verdad Gallardo
Pogea Racing's 964 Porsche 911 Reimagination Stands Out in a Crowded Field
Verdad Gallardo
6 Convertible Top MYTHS Most People Don't Understand!
Michael S. Palmer
2026 Porsche 911 Club Coupe is Spectacular, And Everything Wrong with the Porsche Market
Joe Kucinski
Talos Takes Your 991 Porsche 911 GT3 to the Next Level for a Cool $1.13 Million
Verdad Gallardo
9 Vehicles Porsche Helped Engineer that Aren't Porsches
Verdad Gallardo
9 Features and Characteristics That Only Porsche People Understand
Verdad Gallardo
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way
Joe Kucinski
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)
Verdad Gallardo
Thread Starter
Straight to Video
Rennlist Member
Rennlist Member
Joined: Jan 2004
Posts: 3,599
Likes: 0
From: Los Gatos, CA
Thanks all for the tips!
Mike are you referring to the camber angle numbers? I'll have to dig them up, but left mine stock giving mild understeer and good wear at the back... rears may well make it to 15k
Mike are you referring to the camber angle numbers? I'll have to dig them up, but left mine stock giving mild understeer and good wear at the back... rears may well make it to 15k