Measuring tire temps at AX, What am I doing wrong? Options

[Joseph Mills]

At the last AX, after several runs, I went from 36# to 30# for the front tires (Hoosiers). At 32# and above, the inside was about 5 deg. hotter than the outside. Below 30# the outside started heating. At 30# they were about 117 deg. all the way across the tire. Good. And the car does not push.

The rear tires were about the same temps. However, even when I went as low as 26#, they are STILL about 6+ deg. hotter on the inside. And at 26# the car was starting to get a little loose, but easily controllable. Below are some things I've considered, but really, I don't know where to go from here.

My car does have 1/2 deg more neg camber in the back than the front....

It was a short AX - around 38 sec's with some straight ahead driving - which would tend to heat the inside tread....?

Maybe I need a faster/longer AX? Or can you only do proper readings on a skid pad or figure 8 only....?

Could the engine heat up the inside of the tires? Usually spend 5 -10 minutes with engine idling and slowly creeping up the line.....???

My "pyrometer" is very cheap, but seems to be very reliable with repeated readings.

Any ideas out there??? HELP! (IMG:style_emoticons/default/ph34r.gif)

[Joseph Mills]

A 5 degreee temp variation is not something you should worry about.  At an auto X the temps won't get high enough to be real accurate anyway.

Thanks Chris.

Several emails I got off-list suggested that I try a skidpad for more accurate readings. And from reading your comments, maybe this is what I need to try.

I know I need to use a "tall" gear to minimize the effect of throttle on a skidpad, but that's about it. Do you have any suggestions or tips?

What size diameter should a skidpad be anyway? Does it matter if I take readings across the tire, make adjustments and go on, or should the tires cool back down some after adjusting before another run?