Psi for slicks

[4VCLEVO]

I am trile fitting the slicks tomorrow to see if I need to raise the suspension. What pressure do I need at the strip? Tyres are 15x28x10.5 mt et slicks. I will be hitting the track next weekend.

[GTP owner]

It depends....so you will need to experiment.
I run 9.5psi cold, which goes up to around 11.5psi hot. When i can't get enough heat they are fairly wobbly!
Anywhere between 9 and 12 psi is acceptable. You need to carefully look at the slick after your run and look for the fine cross lines. If they are all the way across then you have a good plant of the tyre. If they are only in the centre = too high. If they are different thickness from the centre compared to the outside = too low.
You can also look at the tyre track left after launch. A pit-crew can check it for an even black left after your launch.

So I would start with 11psi in the pits and go from there. It all depends on how big your burnout is, how hot the day is, and how hot the track is.

[CYC06T]

Originally Posted by GTP owner

It depends....so you will need to experiment.
I run 9.5psi cold, which goes up to around 11.5psi hot. When i can't get enough heat they are fairly wobbly!
Anywhere between 9 and 12 psi is acceptable. You need to carefully look at the slick after your run and look for the fine cross lines. If they are all the way across then you have a good plant of the tyre. If they are only in the centre = too high. If they are different thickness from the centre compared to the outside = too low.
You can also look at the tyre track left after launch. A pit-crew can check it for an even black left after your launch.

So I would start with 11psi in the pits and go from there. It all depends on how big your burnout is, how hot the day is, and how hot the track is.

Spot on. I run 9.5-11 psi depending on the conditions on that same tyre. I run the hard wall tyre as the car is pretty heavy. Keeps the car from getting too wobbly at speed.

[4VCLEVO]

Thanks for the replies. I have done plenty of racing in the past but this will be the first time on slicks.

[prasac]

how heavy is the car? what suspension setup? power? stiff sidewall or normal?

with the same slicks (stiff sidewall) found 11-12psi (cold) the best (3100lbs) we were able to get consistent 1.29 60's.

with lower pressure the tyres would wrinkle too much, the wheel would almost hit the ground. some wrinkle is good but not too much. if u can get someone to photo or video you launching and in the stands as it goes down the track, the data you get from it is awesome. some people change pressures willy nilly and think that it's no good etc, but, it could just be the track and not the tyre itself. with the video you get to see exactly what is happening.

[my67xr]

you can give it a bit of a launch on some concrete too, then check the marks left on the ground.
as posted above,
darker edges - not enough pressure
darker centre - too much pressure
even marks - good

im not sure if you will need them,
but you should really have conventional/race front tyres too with slicks on the back.
the rear end will feel a little "floaty" too with slicks compared to steel belted tyres.

[duster 408]

agree MRXR67, I found using that same slick with a 3550 pound bb xb i had to run 15 - 17psi because of the weight of the car with the downforce on the tyres at launch.the easiest way to tell your tyre pressure being correct is after your burn out draw a chalk line straight across the tread, after you have done the run make sure the chalk has been worn off all the way across.if not adjust your pressures acordingly.

[4VCLEVO]

The tyre is the standard 28x10.5, part no. 3055. Car is a full weight xa gt, don't know exact weight. Has 90/10's with 6cyl springs in the front and I'll drop the sway bar at the strip, also has the factory tramp rods up back. The engine has around 500fwhp, c4 full manual with 4500rpm stall, 4.22 gears. I do have moroso drag specials up front.