[FBTO]

I have a question for all of you track guys. I am running my stock PS2's on the track right now. Hoping to buy some track tires soon, but for the time being, these are my track tires. I know after a session, the PSI's go up from the stock 35 to over 45 PSI. Should I be dropping that to say 40 PSI right after I get off the track session. And then maybe also check again after the next few sessions? If it goes above 40, keep bring it back to 40? Or is the tire going to cool down enough between sessions? I have some really bad tire wear on my left front tire which could be becase I dropped the pressure too low after a hot session?

Any thoughts?

 

[trackaddict]

I had Bridgestone on mine and I tracked them alot. I'd got them up to 42psi cold and check the pressure and wear pattern on eah tire as soon as I got back from each session. The best reference point is the TWI (triangle on the tire shoulder). The sweet spot is at the tip of the triangle indicating the right pressure at that session regarding the ambient and track temperature, loading factor and driving pattern. You need to record them with all the variable conditions with weather and track in order to fine- tune the right pressure for your tires. Add pressure if wearing below the tip and bleed if wearing higher. It's good fun to start playing with your pressure and note the different performance of the your tires. It's safe to add pressure as long as it's below the max cold inflation pressure indicated on the side wall. Underinflation will do more damage than overinflation most of the time. That is my personal experience to share. Other track guys please chime in. I'm tracking with Nitto Invo now and still doing the same with them.

 

[nathanw]

One other thing you can do with the tires is find what gives you the best track wear characteristics, and have the tires filled with "nitrogen" to that pressure. Nitrogen does not change pressure with regards of temp and you should be able to have it done locally for around $60.00 Hope this helps.

 

[Nightspore68]

Nitrogen????

I wasn't sure how to prepare my PS2s for track use and so left them at the factory spec, 36 psi. They wore out fast on a road course, at the outer edges anyway. I think maybe a boost is in order next time to more evenly distribute the wear. What a few of my friends do is chalk the sidewall up to the tread and then after a run see how much chalk rubbed away, then alter the pressure accordingly.

As far as performance, the car seemed fine at stock, but next time I think I'll start out a little higher and see if there's any improvement in handling or wear.

Nathanw, I don't understand the nitrogen argument. Have you seen this in action? Air is already 80% nitrogen. And nitrogen is just as beholden to the ideal gas law http://en.wikipedia.org/wiki/Ideal_gas_law as any other gas, PV=nRT. Why would it not change pressure with temperature?

Anyone who uses nitrogen at the track, I'd be interested to see if the pressure really does remain constant.

 

[Nightspore68]

Oh, I forgot the say that only the front tires wore out at 36 psi. The backs barely wore at all, so I plan to stick with 36 psi for them.

 

[FChampOH]

FBTO,
it is natural for tire pressures to increase while on the track because of the heat/friction being forced onto the tire. I wouldn't bleed them as soon as you come off the track. Just check them before you head out for the next session to make sure they are at the psi you determine works best for you.
There is only so much you can do with a street tire and stock suspension on the track. It's kinda of a catch 22, as in you can increase psi in a front tire to try and help stiffen the sidewall a little but at the same time the increase in psi will make your contact patch on the ground smaller. You'll have to find that sweet spot that works best for your car the it is set up now and your driving style. If you are seeing a lot of wear on the left front tire I'm guessing there are a lot of right turns on the track. It is real easy also to overdrive a tire that is only 225 mm wide on the front of an IS-F as well.
If you plan on tracking your car regularly, think about 18" track wheels and tires (read: wider wheels and tires ) and even a coil over set up with some stiffer springs. The lower ride height (center of gravity), ability to make more of a 50/50 weight bias, and a bigger, stickier footprint will make you smile from ear to ear. (Don't forget some Hawk brake pads to make you stop even better)

Hope some of this helps,

Doug

 

[alexzxlex]

As a general rule for tire PSI with regaed to track purposes here are the facts. A tire should see an increase of 10-15% in PSI from cold PSI.... After a track session. A session consists of 15-20 minutes. Now if the PSI is 20% or more than cold it means you are overheating the tires. That means you need more PSI cold. Conversly, if PSI increase is less than 10% you should start the session with less PSI. I start most of my tires at 32PSI for the track & adjust acordingly. NJMP Lightning June 12, hope no rain. Video to follow.