Track tire psi inflation

[rapter]

Owners manual is asking for 44/45r psi for speeds above 150km/h. seems high...

For those of you on the track with the stock tires, what psi have you been running?

Anyone running at street psi?

For under 150km/h manual asks for 34/35r

[Franklin Joseph]

was at the track monday.
I started high cold psi, and after my first short session, it was around 42/43psi hot and it felt kinda greasy at the end.
I dropped it down to 39psi hot and it felt much better throughout the day. Next morning cold temps were 33psi.

[MDORPHN]

PS2s are happiest 38 psi - 39 psi hot.

Neil

[molie]

38-40psi hot and no more than that for PS2's IMHO.

[crumb]

Forgive me if this is a dumb question, but what happens when a performance tire like the PS2 is punctured at high speed? Assuming a front tire goes, is it possible to avoid a catastrophic wipeout?

[Dan Parker]

As others said, anything over 40 psi hot is very greasy. I found going out with bone cold tires it was better to run the fronts 1-2 psi higher than the rears. The softer sidewall in the rear cut down on the sideways action....a little.

ideal hot psi:
fronts - 39
rear 37

[Dan Parker]

Forgive me if this is a dumb question, but what happens when a performance tire like the PS2 is punctured at high speed? Assuming a front tire goes, is it possible to avoid a catastrophic wipeout?

"Every accident has one thing in common. There is a point in time when it could have been avoided."

Catastrophic wipeout?
It depends on where the puncture is. It's no different than any other non run flat tire. A sidewall puncture can result in very bad things (boom) while a simple cut tire in the middle of the tread will probably just go flat in 10-30 seconds, usually no where near pit entrance.

[johnnyb84]

So if you're having a 20 min session every hour, you'd check pressures after the session, adjust them to 39 front and 37 rear, and then 40 mins later you're good to go?

[Franklin Joseph]

Originally Posted by johnnyb84

So if you're having a 20 min session every hour, you'd check pressures after the session, adjust them to 39 front and 37 rear, and then 40 mins later you're good to go?

40mins later it would have cooled down and psi would drop, in hopes that on the next session, pressure builds up to the desired hot psi. You then adjust after that session if needed.

[Beedub]

so should we be aiming for 35psi cold on ps2??? this should take up to 40psi hot?? about right??

[Dan Parker]

Ideally you should do some hot laps, pit and have someone adjust your pressures to the ideal hot pressures (or 1 psi lower), and go back out. Doing a cool down lap at the end of a session and then driving into the paddock means the psi isn't accurate.

"so should we be aiming for 35psi cold on ps2??? this should take up to 40psi hot?? about right??"

That's a good starting point but depending on temps, the track, and your driving style you could be off. I went out with 36 all around and came in with several tires pushing 42-44 psi. It was bloody hot out.

[MDORPHN]

It's been a couple of years since I ran PS2s on the track, but I likely gained 6-8psi front.

Rear would gain a bit less. For that reason, I usually started with 1psi more in the rear than the front.

So I'd start somewhere around 32 front and 33 rear. I'd then check pressures after coming off a hot lap and, if pressure adjustment needed, bleed them down to 38 - 39.

[EDIT: Looks like Dan and I are saying the same thing, differently]

Neil

[rapter]

Ran my tires at mosport yesterday at 41/42 and in places it was still a little slick

Overall it was an amazing ride!