14 replies to this topic

[John Woods]

Fluke Corporation makes thermometers that are used by race engineers to measure tire temps.
The link below goes to a page on their site related to tire temps and setup tuning.
It includes a graphic showing the info below, along with the article on tire temps.

https://www.fluke.com...e/racetracktemp

From the table:

"Use the following table as a general guideline to interpret readings and make adjustments to the car:

Symptom Diagnosis

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

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

Inner edge hotter than outer
Too much negative camber

Outer edge hotter than inner
Not enough negative camber or too much toe-in

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

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

Front tires hotter than rear
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

Rear tires hotter than front
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"

Edited by John Woods, Aug 29 2016 - 02:21 PM.

[Robert Fleurke]

Thanks John, that's nice and short helpful info to setup the car properly

[tikfas]

Thanks John,always with helpful infos!!!

[gliebzeit]

Always very helpful.  Thank you John.  

[John Woods]

Well when you are not smart enough or at all fast enough its sort of good enough to be a little bit stupid lucky once in awhile. Or have a chart.
Stumbled on the site and the page while trying to figure out how tracks rubber in.

Appreciation belongs to Fluke.com for support of racing and race tech.
Thanks very much for the comments.

Edited by John Woods, Aug 30 2016 - 09:38 AM.

[twinpotter]

Ye thank you John. Excellent info and useful.
Always knew the old rule,if your tyres are worn in the middle,you are over inflated,where if the tyre is worn at the edges,then this indicates too little pressure(Psi)
Didn't realise this relation,but I suppose wear indicates over heating
of tyres and the contact patch
. Well maybe?
This info will go in my set up info folder (for further reading)regarding GPL.

TP:

Edited by twinpotter, Aug 30 2016 - 10:25 AM.

[Michkov]

twinpotter, on Aug 30 2016 - 09:47 AM, said:

Didn't realise this relation,but I suppose wear indicates over heating
of tyres and the contact patch

Not really. Heat leaving aside the transfer from the brakes comes mainly due to rubber stretching. Which it does on the contact patch in case of a tyre. Contact patch size is effected by pressures. Too high and it balloons giving you only the middle to work and vice versa for too little. And that's where the wear comes in wear occurs only at the contact patch. If the pressures are too high the middle of the tread is going to be worn earlier than the edges.

Of course overheating is not going to help with wear, but wear doesn't mean overheating as a general rule.

[Pete Gaimari]

I can give a real world example. I drive a Jeep Wrangler, because I live in the mountains and it's my hunting fishing vehicle. It's lifted a bit and I run 35" tires. They're way oversize for the Jeep, so standard psi won't work. the tires are made for a much larger, heavier vehicle.

So, to get the correct psi in the tires I run a line of chalk across the tread of the tire. Then drive at normal speeds around a large parking lot. I then check the chalk to see how it wore off. If the center of the chalk line is gone I know too much air is in the tires. If the outside chalk line was gone it means not enough psi. I continue with this until the chalk line is worn off evenly across the tread of the tire. In my case that comes out to 21 psi. Anything more or less and the tires wear unevenly.

Race cars are the same. You want the tread of the tire flat on the surface. Keeping camber in mind too. Adjusting it for different tracks.

Don't forget hot and cold psi too. I set my Jeep tires for hot psi. They're a bit soft when cold and would wear the outside edges if I always drove on cold tires. Pretty hard to do.

[twinpotter]

Interesting Pete and nice tip. Tricks of the trade !
I have a 1972/3 Series 3 SWB Landrover with 2 and a quarter diesel motor. Fitted with bigger LWB wheels,which sits it higher and makes it more menacing.
Talk about transgressing here 😎

Now where did I put that chalk 😊

TP:

Edited by twinpotter, Aug 30 2016 - 05:39 PM.

[Pete Gaimari]

A diesel must be nice offroad. Lots of torque.

Here's my Jeep. It had 37" tires in these pics. A small fortune in the running gear too. Wish I had that money back. Sorry for going off topic John.

Edited by Pete Gaimari, Aug 30 2016 - 05:43 PM.

[twinpotter]

Very nice Pete. Bet it's got loads of character.
Mine is a an old girl who keeps on chugging away. Very old and weathered with genuine Capstan winch and spare wheel on bonnet.

Ye apologies John for transgressing.

TP:

[John Woods]

No problems guys. Just having fun and I do appreciate it.
Happy any time someone takes the time to post.

Never heard of the chalk trick. Duh.
Too obvious once you know about it.
Good one. Want to try it.
Sidewalk chalk or tire chalk?

Edited by John Woods, Aug 30 2016 - 08:51 PM.

[Pete Gaimari]

Same type as for school blackboards. I guess that would be sidewalk chalk.

[Pete Gaimari]

twinpotter, on Aug 30 2016 - 06:33 PM, said:

Very nice Pete. Bet it's got loads of character.
Mine is a an old girl who keeps on chugging away. Very old and weathered with genuine Capstan winch and spare wheel on bonnet.

Ye apologies John for transgressing.

TP:

She's a bit more beat up now. That picture was taken when I first built it and living in Big Bear Ca. 2 mo later I moved to Colorado.

[jklhill]

Nice find, John. Thanks for sharing. I need all the help I can get. Printing as I type.