Topic: For Your EYES ONLY Setting tire pressure/camber for racing

[Graywolf]

 CorrectTire pressure/camber is very important for your best results in cornering and fast lap times. You will need a tire pyrometer which measures tire temperature. Run your car for a couple of hot laps at the track. Then do immediate tire temps on all four tires ininnerside surface, center, and outerside surface and record. For best results the inner and outer tire surface temps should be nearly the same. If the outer surface is hotter,there is to much positive camber. This can be corrected by increasing negative camber or by reducing body roll i.e.stiffer sway bar ,cross brace ,etc. If camber is minus 2 already,body roll should be stiffened but at a price-high roll stiffness will reduce adhesion on bumpy corners. The best tire pressures are determined with temps across the tire. If the center tire temp is the same as the average of the edges,then your pressure is about perfect. If the center is higher temp,then the tire is over inflated. If the outer surfaces are hotter,then the tire pressure is to low. This Material is only for the Kappa Community and is not to be shared with competitors and will be considered an act of TREASON!!! Gray Wolf ,Former 7th Special Forces Group

[Gentleman Jack]

Gray wolf,

Secrets are dangerous.  Dangerous is my middle name! Could you also explain how camber is changed and can you use your race set up for street driving?

GJ
I'm not tellin

[snaponbob]

This may be considered heresy, but here goes. Don't waste your money on a contact pyrometer. I own both an infrared (heat gun) that can be had for as little as $35-$45 and a Longacre probe type pyrometer. While the probe (contact) style is a bit more accurate than an infrared, the relative temp readings tend to be the same. In other words, not unlike before/after dyno readings, one is looking for DIFFERENCES in temp readings across the tire but not necessarily the actual temps. An infrared is much quicker and less than cumbersome than a probe style.

Graywolf is pretty much right on the spot with what the readings tell you. For Kappas, there are only three types of sway bars (FE2, FE3, and GXP/Z0K) unless one is going to spend mega bucks on customs, so not many choices are available and thus rough pavement traction should not be an issue. For our cars, springs are a better avenue of attack for better handing as even the GXP/Z0K springs are fairly soft. Camber and pressures ARE the keys for best tire contact. That said, for those that are using wider than 245s (Hoosiers up to 295 section) your butt will have to factored into the temp readings as "squeezed" tires will roll over a bit, so even at 2.5-3.0 degrees negative one will probably see more inside temps than outside except on the edges because a bit extra pressure will be needed to support the sidewalls. With wider rims, lower pressures can be used as the sidewalls will be working better. (In my case, when I ran 315s on 9s I was about 10psi higher than 315s on 11s.) By all means, take notes about surface type and condition (dry, damp, wet), surface temps, ambient temps, and tire temps. After awhile, you'll have a lot of this in your head and will be able to set the initial pressures from memory and go. Something else to remember, corner entry or exit as well as overall handling can be tweaked by going up/down from "perfect". Trial and error is the course at the school of hard knocks for all of this.

Quit comment on set ups. Anything that is run at Solo or track days will work just fine on the street EXCEPT toe settings. Street toe settings are right at zero front and rear for the street, and improper toe setting is what kills tires, not the camber. I have about 2 neg rear and more than 2.5 front, and have had that for four seasons. And my OEM tires have 24,000+ miles on them and still have tread.

[Graywolf]

Agree with your comments,it must also feel good to the driver . One driver may like it and another might want it different. Also this might help you with your evaluations on the various crossbars and chassis stiffening devices. Sure jacking up your car in one stop may demonstrate it is stiffer but it will really show measuring tire temps before and after install of device.

[kennysabarese]

I heard that unless you are running slicks, that the pyrometer stuff is pretty much useless. I can't remember where or who though. I think it was a reliable source.

I can't wait to get a proper alignment.

[snaponbob]

I heard that unless you are running slicks, that the pyrometer stuff is pretty much useless. I can't remember where or who though. I think it was a reliable source.

Whoever said that is wrong. Want proof? Slap on some r-comps, guess at the pressures, and see how long they last. Just look at how many drivers at Tours, Pros, and Nats use pyrometers. Even in the ST classes they are used. Pyrometers are almost a must.

[kennysabarese]

Ok so maybe it was R Comps, but they said don't bother with street tires.

I hope I am wrong. I want to do this on my car.

[Imaj]

R compound tires are a must for track use.

[kennysabarese]

I use my Star Specs on the track. But I am not competing.

[Graywolf]

Gentleman Jack, If your outer tire temp is running higher then you add more negative camber, Inner tire temp higher add more positive camber. But remember 2.5 negative is about as high as you want to go. If tire temp is still high outside then you may want to decrease chassis stiffness in the front or increase stiffness in the rear. You should be ok with tire wear according to other members on the forum. I only have 6,000 miles on my car and have not seen any unusual tire wear. When setting your camber you should be sitting in the drivers seat or someone of similar weight for best results. Hoosier R take a full lap to warm up and are not great for Solo events Autocx Time Attck etc. For Solo Hoosier A will give you your best time as a rule.

[snaponbob]

Ok so maybe it was R Comps, but they said don't bother with street tires.

I hope I am wrong. I want to do this on my car.

I can assure you that ST class drivers DO use them. They are cheap. Try one.