ilovegt100

I have finally committed to better tires in the form of Michelin Pilot Sport Cups in 225/50/16/7 and 245/45/16/9 for my 87 911 cab for DEs and such. I know many people love or hate these tires but can anybody who likes these tires suggest good starting cold and target hot pressures for me? Also, if anybody would like to comment on their pressure settings for autoX that would be helpful- knowing full well that the forum consensus seems to be that they are suboptimal in autoX but better than street rubber. Thanks!

mhm993

Go to the tire rack web page, and look up the "care and feeding for mpsc's" link in their technical area....tells you all about hot and cold and wet and dry pressures.
(And don't use them for AX----what's the point of being bumped into a performance category for tires that aren't performers, and cost a fortune?)

Jim Michaels

I agree with Marc. I think the recommended hot psi for the Cups is in the 32 to 36 range. Where you start them cold to get into that range hot depends on ambient and track temperatures, and how hard you drive on them. At my last outing (ambient temps in the 70's) I started them at 28 psi at each end for the first session to reach about 35 psi hot. They take about two laps to build heat and grip on track, but stick very well after that, assuming they're in the recommended psi range (they're very sensitive to psi). As Marc said, they won't provide much grip at autocross because they don't get hot enough. Thus, they are good on track, but barely better than good street tires at autocross. The same hot psi range works for autocross, but you can start them at a higher psi cold than for track (maybe 30 to 32 psi), because they won't gain much pressure during a run.