I'll be driving up to Thunderhill for a track day this weekend. Weather's supposed to be pretty cool, between 33F and 49F but no rain. My track tires are Michelin Pilot Sport Cups, my streets are Dunlop Direzza Sport Z1 Star Spec. Will the Michelin PSCs run OK in this temperature range, or should I use my street Direzzas? I normally run 38F/34R pressures, should I use a different number in this cold? I'd like to use the PSCs unless it's not prudent.

 

I run up there. The track stays cold unless the sun is on it this time of year. A lot of guys run the street tires but bring the Rcomps. I've run street tires there and it was a lot less sketchy than the guys with the Toyos. But I guess if you can maintain the temps in the tires and do some moderate warmup laps you could wing it.

 

I've done a number of November events at Lime Rock where it has been cold enough to snow during proceedings. Every time I thought I might be doing better on the street tires, I proceeded to go way the hell faster when I switched to track tires (Hoosiers or Kumhos).

I generally aim for 38psi hot pressures all around. My cold pressures are usually ~31F/29R IIRC...

However, Michelin recommends 32F/36R hot pressures for the PSC (seems bizarre to me that they should differ in the general guidelines, surely any front/rear differences would be dependent on the car being driven!).
http://www.tirerack.com/tires/tiretech/gen...and_Feeding.pdf

I'd run the PSC's, probably at 36 hot front and back.