Tire Pressure (need some advise)

[onefastgokart]

I've heard that I should increase the PSI in my tires a little bit higher for track use. I've also heard that I should not increase the PSI in my tires. Which one is correct? If both are correct then which one should I follow?

When I was at NHMS-2, I was having some trouble with getting the right PSI. I believe I was told by my instructor that I want my PSI to be (38 PSI COLD). What happened was my rear tire(s) got hot (PSI Increased) and when I took a corner, the cars back-end wanted to get out.

I'll be running on 165/55-16 87V Tires. At what (Cold) PSI should I sit my tires to, for track use?

I realize that I'll have to adjust things well at the track because of things like Temperature Changes. Suppose to be 38 Low and 59 High for Saturday. I know that after a session, I should check my tires, to make sure that all rubber is hitting the pavement correctly, meaning that my tires aren't to low or to high. I remember someone mentioning something about using a piece of chalk on the tires however I don't remember where I should put the chalk on the tires. Could someone tell me?

Any help on this topic would be appreciated.

-Adam

[CP]

Check your pressures right after you come in from a session and adjust to your target pressure, adding or subtracting as needed. I keep a logbook so the next time I'm at that particular track I can set my pressures in the morning and hit them dead on most of the time. Remember that for every 10* drop in outside temperature you'll need to add a pound of air. If you were getting oversteer, drop the rear pressures 2psi and see how it feels.

[onefastgokart]

Okay, thanks.

I made a little log sheet via Spreadsheet to help me keep track of my Tire Pressure this weekend.

-Adam

[brucesallen]

If you are running stock suspension you will need to have the tires 3-5 psi above stock when cold. several pounds Higher when hot. Stock suspension will allow positive camber on the outside tires in a corner with the result that you are running on the edges. This is why large aftermarket square sided tires on stock suspension may have worse grip than stock tires. Increased pressure on stock tires will create a rounded face so even with positive camber you will still be running on part of the face. Very stiff race suspensions are capable of keeping the tires flat on the face and do not need increased cold pressure.

At NHMS especially on front wheel drive vehicles, the right front tire does most of the work and gets hotter. Next is right rear, then left front. Left rear can be taken off and stowed as it does nothing. So all this means that Pressures should be set differently. LR=highest, RF=lowest. Checking tire pressure and sidewall wear after a run will allow you to fine tune the starting pressure. 42-44 hot is not bad.

[CP]

FWIW: on my Spec Miata my tire pressures rise @7-10psi between cold and optimal hot pressure DEPENDING ON WHICH CORNER WE'RE LOOKING AT. Right rear always has the biggest differential.

[DanB]

In both the Datsun (2300 lb., street/track compromise suspension, 225/50-14 tires) and in the Honda (2750 lb., stock suspension, 205/55-16 225/50-16 tires) I run cold pressures of ~31/30psi front and ~29/28psi rear at the track to get 38psi hot.

So I run lower cold pressures at the track than I do on the street...

[onefastgokart]

Well, I had the Tire Pressures set at 35 PSI yesterday and didn't run into any problems like last time (July). I must say though, I prefer running on 16's instead of 18's.

Also......

See you all on the track today!! (Oct 10th) - That's right! I got signed off to go Solo. (Haven't been recommended license but hopefully that will happen soon). P.S. - I will do my best and give it my all, so that I don't slow anyone down and I'll be watching my Mirrors and giving point-by's when needed.

-Adam