I have noticed that when I am autocrossing I only seem to have a small window to get a good lap in. Typically the first run I like to take it steady and make sure i know the course then I have 1 or 2 good runs. After that the tires seem to get too hot and the car gets really loose meaning I cannot get a good time or I spin out. I setup my street tires to about 36 psi and have about 1.7 degrees camber front and 1.3 on the rear.

Would lowering or increasing the pressure when they get hot help increase traction?

I have searched for this but cannot find anything for autocross tires overheating.

 

Just spray them with water between runs. Its a very common practice.

 

You would also normally adjust pressures before making each run. It wouldn't be unusual for the unadjusted pressures to increase by 5 - 10 psig over several autox runs. It's also a common practice to start a few psig below your optimum target pressure for the first run, then adjust the pressures to optimum just prior to making each subsequent run. Once they cool off you may need to add some more air back before starting your first run at the next event/session, so having an air source available (tank, pump, etc.) may be necessary.

edit: you may already be doing this, it isn't clear in your post. What tire brand/model are you referring to?


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i do this and it works very well however i had some time to talk to a guy from tire rack who does reviews for grass roots (i dont remember his name) and i was told that although the tires may start to feel greasy and inaccurate they actually have a higher level of grip. so if you can deal with the sloppy feel you will actually be faster. i should note that he did say he usually cools his down as he would rather have the accuracy.

 

^^^
I'd love to see the data on that.

 

you and me both but im sure the guy knows more about tires than me or i would guess anyone on this site. i really should look up his name....

 

Likely Woody or Trent, both of whom ran a B Stock RX-8 on the past. But the test results mean a lot less than the race results.

 

maybe one specific tire worked well with that method, but not all.

 

Works for the V710 and A6. And in the ST ranks we have seen that many of the tires require cooling between runs.

 

usually only if there is a second driver or the heat of summer is in high gear, there are other variables though like how much time between runs etc. so it can vary a bit

 

I was agreeing with you, not him - wasn't clear my fault!

 

I am running the Dunlop Star Spec, I find that if I get a brake between runs they perform much better. I will make sure I check every run. I always check after the first but then sometime get too busy talking. Thanks for the tip on going lower with the pressures I wil try that. My current front tires are not Star specs and are not very good (280 tread wear and on the wear bars). I have the Star specs for the front and will be fitting them before my next event so hopefully I will see an improvement. Thanks for the help.

 

I did 6 runs a few weeks back and on each run lowered the tire pressures by 2 PSI starting at 40 going down to 30 and noticed that the best run was 32 PSI although the car felt really sloppy it was faster. I try running a lower pressure and try to adapt to the sloppy feel see if it ends up quicker.