cagotzmann

To start I am using "Michelin super sport tires" This is not a dedicated track car. (1978 corvette)

The only way I can get tire temps is after our cool down lap and come into the pits. How much does this effect tire temps ?

What kind of temperatures are you guys getting after a session.

Mine are in the range 145-160.

What are you guys using to determine good contact patch. I see some people at the track marking the tires to see how much they roll over etc.

I would like to get maximum tire life, understand if I have too much camber or not enough, correct tire pressures etc.

As for tire pressure I am aiming for 38 PSI when I come off the track.

As for camber I have been looking at even tire wear.

The main problem I see now is my front left tire. This tire wears more than the others. This may be due to the track I drive is mainly right hand turns, and 1 turn is a slightly sloped 180 degree turn at about 56 MPH.

I am trying to determine if I am over driving the tires or I don't have the correct setup yet.

Bill32

The effect of a cool down lap and even worse, coming into the pits is huge.

And if you're using an IR gun, you won't get accurate readings because the surface of the tire cools down rapidly.

If you're just interested in overall temps, that's fine but it won't help you with the contact patch.

You can get a better reading by pushing the car in the corners during the cool down lap (short shift, cool the motor but keep the tires working in the corners), pull off at the hot pit exit and take the readings. And its way better to use a probe pyrometer to get below the tire surface (even a cheap one).

The only way (and the best) to use temps to work with the contact patch is to take 3 readings per tire with a probe and determine if the tire pressure needs changed (plus you have to take into account the camber effect on the inside reading). And this has to be done as close to on track temps as possible because the outside of the tires cool down slower than the center of the tire (the center has thinner rubber).

mikeCsix

Problems:
With mostly right hand turns, the left front is going to wear more than the others. No way around it.

I shoot for 30psi hot with Michelin PSS's, so I start at 27 psi except for the front outside tire, its at 26. That is for the first session only, when I come in I bleed down to 30psi if needed. Lots of variables.

Good comments on the temp gauge to use, mine is an IR and as mentioned it isn't accurate. Maybe for HVAC work, but not tire surface temps.

I use the pfadt specs, track setting for street tires as a ball park, experiment incrementally as needed or desired.

Joshboody

I had 1 session with probe temps few events ago, which I think my pressures were good that day. But I’m a newbie and still learning. Log as much data as possible each session… even if only tire pressures to start. You’ll gradually start being able to relate pressures/wear to driving to lap times. And I ask everyone

C5 Z51 stock weight +200lbs
Camber: F 2.2 / R 1.0
tire: NT05 275/17
Track: low speed / clockwise
Ambient: 100deg

Pressure
Cold: 26 all 4
Hot:
36 33
35 34

Temps:
190 190 188 / 184 177 170
191 191 189 / 187 182 172

Pitted fairly hot, about ¼ lap cool down

Bill32

Your temps look pretty darn good ( shows you were working them pretty hard), I would have dropped the LF by at least 1 psi and taken another reading. I'd also try to find out what the manufacturer says is optimum temp.

I usually don't work about anything under 5 degrees, outside to center (but we start out at 11 psi cold).

The other thing you can do is add up both outside temps, divide by 2 and compare to the center temp though I prefer to look at the raw numbers.

And remember that the pressure increase will vary by the amount of moisture in the air that you use.

We keep a pressure/temp log book on the cars.

Bill32

A single read probe pyrometer runs about $100 these days, Harbor Freight used to sell one for about half that that worked OK.

Mine is kinda pricy but it takes all 12 readings at one time and can store 10 sets of readings.

An IR gun is still handy at the track though, taking track surface temps, brake rotor temps etc.

Joshboody

Thanks for the comments.
That day I gained good understanding of my pressures with just 1 session of temps... it kinda confirmed what I was feeling on track and seeing in wear. Since then I've centered on 34 loaded and 33 unloaded for NT05 pressures. And from the center wear almost seems I could go little lower.