alexb76

You basically need enough PSI Air pressure to give you the right balance of contact patch and sidewall flex. The nominal balance is 33/39 at cold temp (20 celcius).

To give you an example, when I track, and my temps raise, the PSI goes up significantly and to ensure I got the right handling, I have to DROP the PSI when it's hot, to 37/44 max, and then will have to rise it after I am done tracking as my cold PSI will now be below the 33/39.

For me, I keep it simple, I try to keep the PSI between 33/39 - 37/44 in all temps. Like if it's way too hot, and I am sitting at 39/46, I drop the PSI, if then I am in middle of winter and my air pressure goes down to 31/37, I will add air to compensate for the drop, and so on...

alexb76

Exactly! +1

hakaida702

Since there's no way I can fill it cold here. I live way out in the burbs and nearest gas station is far out. I'll just fill each tire up over and then I'll wait til morning to bleed it down to the correct cold temp.

alexb76

You worry too much... the main purpose of doing it at cold temp, is that they do NOT want you to go too low if you got the tire hot. Like let's say you drove in 100 MPH in hot climate, stopped at a gas station and saw you're PSI is too high, you don't wanna go to 33/39 hot, because then the next morning out of garage (if it's cold) you'd be lower than 33 for sure.

So, in your climate, as I said, keep your pressure between 33/39 and 37/44 and you're all good. It doesn't matter. Basically if at your coldest time (early morning), you're sitting at 33/39, you're good to go!

mdrums

That will work...if you want to really get close fill them up 4lbs higher than cold. Under normal summer street driving in hot weather you will get a psi increase of around 4lbs per tire....3-4 is what I see on the street.

mdrums

Also something else to think about and ponder.....LOL....at the track most all tires lose grip and slip more at any HOT pressure higher than 38lbs.
For 997 Porsches...MPSC likes 32/35 hot, PS2 likes 35/38 hot, Pirelli Trofeo likes 30/32 hot, Toyo R888 likes 32/35 hot.
I always find it funny when guys think that higher psi is for more sporty driving....it's quite the opposite.

hakaida702

Yeah I do worry too much. It started when last week I got the air pressure warning idiot lamp when I started the car. Now I just want to get it done right and not worry about it.

ADias

Mike: Yes, of course, but 34/37 is referenced to a cold temp of 20C/68F. If the 'cold' temp is different, the pressure should be adjusted according to the curve. And yes, I agree with you, many run with too much pressure. I recommend 32/36 for M-PSS set at 68F.