Hey guys I was wondering what tyre pressure I should start out with cold tyres on the morning of my first track day coming up.


They will be nitrogen filled, the placard on the door frame says light load 34/40 psi.


I was thinking something like 33/39 to allow the nitrogen to expand 1 psi, which will bring it to oem after a few laps, or do you think I need to start even lower?


Cheers

 

There are quite a few threads on track tire temps. I start mine at 32/35 and keep the temp spread constant. I also keep the hot rear pressure at 39 or lower as the rear tires get greasy at 40 and above. My street pressure is 34/37 cold.

Eric

 

I thought all the claims of advantages for the use of N2 in automobile tires had been debunked. We used it in fighters in the Marines because of the extreme altitude and temp fluctuations that jets encounter that are light years beyond what an automibile encounters.

 

Thanks. Ive read all the posts on this but am no closer to knowing what to put in. All I know is the advised pressure is 34/40 but on a track using regular o2 this would see the rear tyres hit nearly 50 psi. I checked my tyre pressure once after several hours of street use and the rears were 44 psi.

I think 32/35 is a good suggestion. Maybe even 30/35 or bleed off the pressure in the pits. I have seen posts where owners have started with 28 psi in their front tyres at a track event.

 

I don't track my wife's '08 c4 but the door recommended pressure is (if i remember correctly) 37-44. The asphalt in Texas summers is extreme and with the increase it gets so rough it is intolerable, so i usually run 34/39 in summer. I'll bring it up a little as the days get cooler.
I'm sure with the speeds and extreme heat from the brakes that 32/35 would do well in the track...as long as you don't hit any real bumps the 1st few laps.

 

The correct air pressure may be a trial and error process. It depends on track temperature, track conditions, your driving style and the brand of tire you are using. For example, at Laguna Seca I'll start at 32F and 35R and adjust from there depending on conditions. It's helpful to have a good tire guage so you know exactly what your pressure is and how your car responds (all other things being equal).

 

Thanks, yep I just bought a tyre gauge deflator off ebay for $30. Ill start with 32/35 and go from there. The car isn't a daily drive so when I do drive it I tend to drive it hard and have fun. So even the next day when the tyres are cold and go back to 32/35 it should be fine as it will heat up again prettt quickly. Or I can just add a couple psi of O2 to the nitrogen filled tyres shouldn't harm it mixing 95% Nitrogen and 5% O2 since O2 is 70% Nitrogen anyway its really about 2%.

 

Tracking a car with street tires requires a higher hot pressure for the tires to work. Usually in the 45-48 psi range.


Nitrogen will still allow the tire pressure to rise, but as the tire reaches operating temps the tire pressure rise will slow and stay more constant. This is the advantage of nitrogen for track use.

 

I have seen posts where owners have started with 28 psi in their front tyres at a track event.