The Track LOWERED my Tire Pressure??

[TexasChuck]

My first time at a track was yesterday. With an instructor, not an event. I put my tires at 39 psi at home cold tires. Temps in the mid 50s. Then when the track's tech checked my car, after us driving there (45 miles) in 60 degree temps, the tires showed 45 psi, and the tech lowered the pressure to 38. Me being a complete novice accepted this. The actual drive time on the track was a lead follow thing, with me following the instructor (he in his car/me in mine). I could feel the softness in the tires. I know in auto X you want the tire harder just to keep them from rolling off the rim when cornering hard. And I felt like I was cornering pretty hard, but of course nothing like a more experienced driver would. So, I'm confused .
Any experienced input will be helpful.
Thanks

[ENT-Z]

Your tire temps are going to increase dramatically when you drive on the track, therefore you want to start with a lower pressure than you would normally run on the street. I start my tires at around 30 psi and when I come in from a session they are usually 35 psi which for my RE-11s works very well. If you would have checked your pressures after your session I expect they would have went up - the harder you drove the higher the pressure would have gone up.

[TexasChuck]

Now, that makes sense! Thanks

[ResIpsa]

Originally Posted by TexasChuck

My first time at a track was yesterday. With an instructor, not an event. I put my tires at 39 psi at home cold tires. Temps in the mid 50s. Then when the track's tech checked my car, after us driving there (45 miles) in 60 degree temps, the tires showed 45 psi, and the tech lowered the pressure to 38. Me being a complete novice accepted this. The actual drive time on the track was a lead follow thing, with me following the instructor (he in his car/me in mine). I could feel the softness in the tires. I know in auto X you want the tire harder just to keep them from rolling off the rim when cornering hard. And I felt like I was cornering pretty hard, but of course nothing like a more experienced driver would. So, I'm confused .
Any experienced input will be helpful.
Thanks

First of all, where did you hear that running 39 psi on cold tires was proper or that tires “roll off the rim when cornering”? I will take a guess that this comes from some forum “expert”.

Remember, advice you receive from someone at the track is almost always better than anything you read on this forum. That track tech was absolutely correct in lowering your tire pressure to 38 psi (he probably wanted to lower it more but did not want to hurt your feelings).

Sure, tires inflated to 45 psi are going to feel stiffer but the tire was not designed to operate at that pressure. You need to relearn what it feels like to drive on tires inflated to 35 psi. Of course there are no hard and fast rules. There may be times when you will need to run such high pressure (such as the Bonneville Salt Flats or tracking on snow tires).

[TexasChuck]

Thanks to ResIpsa,
The 38 cold (not 39) comes from the recommended tire pressure on the door jamb of the car, the other from, yes forum "expert". I try to keep an open mind when it comes to reading many opinions on various websites. That's why I asked for "experienced" info.
And your's and ENT-Z input, I believe, is accurate and informative.
Thanks,
TxCh

[Eagle]

Congrats on your first track day! I did my first in January

If i'm not mistaken the cold tire pressure of our cars is supposed to be 35 psi, right? Or is it different for the roadster?

Anyway, if you watch your dash you'd notice that your TPMS light probably came on after the track tech lowered your pressure. This is completely normal. Then after a few laps the TPMS light turns off because your tire temps have gone up, therefore increasing volume and pressure.

When I hit the track the first time I almost forgot to drop my pressure, I dropped it from 35psi to around 29psi. You definitely don't want to blow a tire on the track