Suspension tweaks based on these tire temps?

[Daytona Dan]

At the end of last trackday season I finally bought a tire pyrometer, the Longacre model with 12 temp memory. My best laps at Watkins Glen yielded the following temps noted below. For those not familiar, the readings are oriented as if you are looking down at the car from above it with outside, inside, and middle of tire readings for each tire. Bear in mind that these temps are not hot pit stops, but were taken by me after rolling back into the paddock and jumping out of the car so overall temps would definitely be higher.

124/120/133 135/107/105

131/134/142 142/127/124

Based on these temps I think our tire widths are OK (i.e. within the acceptable heat range), but it looks as though we need to put a bit more positive camber back into the car based on the readings across the tires. I am currently at Negative 1.9 Front / Negative 1.5 Rear with 295 / 335 Hoosier R6s. I am considering taking out a bit of the negatiive camber based on these readings, particularly the passenger side because the passenger side inside/outside temp differential is more extreme (20 – 30 degrees differential) than the driver side (10 degree differential).

Any thoughts from those with suspension tuning experience?

[Gordon Levy]

Left front- more neg camber, probably lower tire pressure also around 2-3 psi Right front- less neg camber and reduce tire pressure
Left rear- Les tire pressure, probably about 4 psi Right rear- less tire pressure probably about 4 psi

[Daytona Dan]

Thanks for the feedback Gordon. Should have also mentioned that I am at about 20/21 psi front/rear. Would running in the high teens be too low?

[Gordon Levy]

My car runs 275/315 and might be a tad lighter than yours and I am running almost 3 degrees neg camber and I start cold temps at 16 on all 4. I get about 6psi heat increase and very even 175-190 degree temps all the way across.

[CHOTIS BILL]

I put your numbers in a program that I have and it came out with:

LF +1.7 psi
.45 degree less negative camber

RF +2.6 PSI
1.5 degree less negative camber


LR .no change in PSI
.55 degree less negative camber

RR +1.2 PSI
.9 degree less negative camber




This program adjusts the suspension so that the tire temperatures are even across the tread but I have found that on full boded cars the inside edge should be 10 deg to 20 deg hotter that the outside edge so you need to take that into consideration but I found the PSI change recommended was always very close at least on the tires I was running. YMMV

Bill Lomenick

[Mark Dougherty]

Bill
what program is that
i am always interested in learning more.
Thanks
mark D

[Gordon Levy]

I have a tire temp analizer program also that works well. Once you imput the corner weights, tire sizes and pressures it will help you with what changes you need to make. You also need to imput all your lap times.
The ideal temps you should be seeing is between 165 and 195 degrees. If you can be consistant at 180/185 you will have great grip and tire life.
Where the temps you took after you pulled into your pit or done on the hot pit lane fresh off the track?

[Daytona Dan]

I was solo when these temps were taken so I could only get the temps after rolling back into pits and jumping out of the car. Not sure how much I lost temp wise in those few minutes but assume that I had to have lost some. It was also a 60 degree day late in the season. We'll be back at WGI again on 4/27-28 for an open track event and will be able to do hot pits then. We initially went with most rubber possible but have always wondered how much is too much. 295/335 for me is definitely better balanced than 315/335 but I think my next set of tires may be 275/315 to see what that feels like and what temps those sizes yield.

[CHOTIS BILL]

Dan,

It is one called “Advisor” by Paul Van Valkenburg and runs on a palm Pilot but I don’t think it is for sale anymore. It did a lot of analyzing and gave all kinds of suggestions on suspension setups.

Bill Lomenick