I came across a GREAT post explaining tire temperatures and how much they can tell you about your tire pressures, spring rates, sway bars, etc...

http://www.coleparmer.com/TechLibraryArticle/291

Cliff notes for those who would rather read them here.

2-3 hot laps then record tire temperature as quickly as possible using a pyrometer/thermometer.
IR Pyrometer is expected to be 10-40 degrees colder than actual temperature.
Contact thermometers with a piercing style thermocouple probe are MUCH more accurate.

Record Inner, Center, and Outer for all 4 tires. Inner and outer readings should be about 1in. from the sidewall of the tire.
"Ideal" temperature per tire is dependent on compound.
Refer to manufacturer for the "ideal" temperature.

"A typical operating range for a DOT-R tire is 180°F to 200°F with a hot pressure of 37 to 43 psi. You want to see no more than 20 degrees difference in temperatures across the tread, with the inside being slightly hotter than the outside. " as quoted from the post.

Symptom:
Center hotter than edges
Cause:
Tire pressure too high. Reduce 1 psi for each 5° F delta.

Symptom:
Edges hotter than center
Cause:
Tire pressure too low. Add 1 psi for each 5° F delta.

Symptom:
Inner edge hotter than outer
Cause:
Too much negative camber.

Symptom:
Outer edge hotter than inner
Cause:
Not enough negative camber or too much toe-in.

Symptom:
Tire below ideal temperature range
Cause:
Tire pressure too high, tire too wide, or springs/sway bars too soft at that axle.

Symptom:
Tire above ideal temperature range
Cause:
Tire pressure too low, tire too narrow, or springs/sway bars too stiff at that axle.

Symptom:
Front tires hotter than rear
Cause:
Car is under steering (pushing). Too much front spring/sway bar, not enough rear spring/sway bar, front pressure too low, rear pressure too high, front tires too narrow, rear tires too wide.

Symptom:
Rear tires hotter than front
Cause:
Car is over steering (loose). Too much rear spring/sway bar, not enough front spring/sway bar, rear pressure too low, front pressure too high, rear tires too narrow, front tires too wide.


With this all being said, the idea is to start off with a tire pressure that does not exceed what is on the sidewall. Tire pressures will rise as the tire gets hotter. Do a couple hot laps, record everything, then make adjustments based of the chart above.

Cheers! Hope this helps somebody as much as it helped me.

 

Great guidelines to start with but every track is different.
Every driver is different.
Making a set up sheet is what i was taught for everytime you go to the track.
Outside temperature is also a key factor, as well as others.
Record what changes you make on each run.
Annotate what the car did or didnt do afterwards.


This is why we dont like just giving our set ups to someone because they dont know how to set a car up.
We factor in our experience level vs theirs.
Our cars might have different parts than theirs do.
Driver preference.. do you like it loose or tight, over steer vs under.
How much rotation etc. The list is endless.

But this you posted will help those who want to start to learn how to get the car to handle the way they feel most comfortable driving.
Thanks for posting this.

 

Maybe I am wrong here but doesn't this also assume 0 toe?

I would think - inner tire temp higher is also seen if the tire is toe out, outer higher if tire is toe in?

Am I wrong?

 

Hoosier has some guidelines for you start with as well when running their products.