[Z06] Track tire pressures..
Instructor
Joined: Jul 2002
Posts: 133
Likes: 0
From: Harrisburg PA
Re: Track tire pressures.. (Speedtoy)
I ran 34 PSI in the rear and 38 psi in the front for autoX. It was only the 2nd time out. Need to experiment more. [IMG][/IMG] :chevy :chevy
[Modified by rpuerzer, 2:54 PM 12/6/2002]
[Modified by rpuerzer, 2:54 PM 12/6/2002]
Cruising
Joined: May 2002
Posts: 10
Likes: 1
From: Everett WA
Re: Track tire pressures.. (rpuerzer)
It depends on your suspension setup and how aggressive you are. ie: How much negative camber you have front and rear and how much toe-in on the rear.
One quick way to gauge whether or not you have the correct tire pressure is to place 3 chalk marks equidistant on the shoulders of each tire. If you are rolling the tire (underinflated) the chalk will start to become removed. If you are over inflated the chalk won't be touched. Also look closely at the shoulder area of the tire and you will see some small raised triangles. The wear pattern should just reach the tips of those triangles.
Another good way is to check tire temperatures. Using a tire pyrometer measure the inside, middle and outside of the tread contact area and see if there is any difference. With negative camber dialed in the inner edge will be hotter. Then a gradual decrease to the outside edge. Ideally, the temps should be with in 10 degrees of one another. You can adjust with 1-2# pressure increments. If the mid temp is higher than the edges you're over inflated. If the edges are both hotter than the mid you're under inflated.
If you are running the GY F1-SC's on the track you should start in the 30 psi range cold and adjust accordingly. I find 30 front and 29 rear works well for the GY F1 SC's on an asphalt track. (Checked temps with a tire pyrometer.)
Longacre Racing has good tire guages and pyrometers.
http://www.longacreracing.com
:cheers:
[Modified by No Doubt, 7:02 PM 12/5/2002]
[Modified by No Doubt, 7:03 PM 12/5/2002]
One quick way to gauge whether or not you have the correct tire pressure is to place 3 chalk marks equidistant on the shoulders of each tire. If you are rolling the tire (underinflated) the chalk will start to become removed. If you are over inflated the chalk won't be touched. Also look closely at the shoulder area of the tire and you will see some small raised triangles. The wear pattern should just reach the tips of those triangles.
Another good way is to check tire temperatures. Using a tire pyrometer measure the inside, middle and outside of the tread contact area and see if there is any difference. With negative camber dialed in the inner edge will be hotter. Then a gradual decrease to the outside edge. Ideally, the temps should be with in 10 degrees of one another. You can adjust with 1-2# pressure increments. If the mid temp is higher than the edges you're over inflated. If the edges are both hotter than the mid you're under inflated.
If you are running the GY F1-SC's on the track you should start in the 30 psi range cold and adjust accordingly. I find 30 front and 29 rear works well for the GY F1 SC's on an asphalt track. (Checked temps with a tire pyrometer.)
Longacre Racing has good tire guages and pyrometers.
http://www.longacreracing.com
:cheers:
[Modified by No Doubt, 7:02 PM 12/5/2002]
[Modified by No Doubt, 7:03 PM 12/5/2002]
Racer
Joined: Mar 2002
Posts: 355
Likes: 0
From: Germantown WI
Re: Track tire pressures.. (Speedtoy)
I got some very good advice that I've followed and have enjoyed success with. In Autocross I run 44psi front and 38psi rear. Sounded really extreme to me, till I ran it.. So far it's been perfect.
For track days I have been running 34 front and rear on warm days at fast tracks, 34 on cold days at fast tracks, or warm days on slower tracks. Buttonwillow I ran 34, while Vegas aoutside track was 32, as one tends to get a lot of heat in the tires. These are dead cold tires. What I've been aiming for is 38 to 40psi hot off the track. At that pressure I have seen good pyrometer readings, in the 190 range, shich seems to produce good grip...
Hope this is worth something to you.
For track days I have been running 34 front and rear on warm days at fast tracks, 34 on cold days at fast tracks, or warm days on slower tracks. Buttonwillow I ran 34, while Vegas aoutside track was 32, as one tends to get a lot of heat in the tires. These are dead cold tires. What I've been aiming for is 38 to 40psi hot off the track. At that pressure I have seen good pyrometer readings, in the 190 range, shich seems to produce good grip...
Hope this is worth something to you.
