[JimD]

Has anyone had a really bad experience while running Michelin PSS with a tire pressure of about 40 psi? It seems like the problem may not be the tire, it may be the pressure.

I tested various pressures on my OEM run flats in an autocross. I used the white material sold to mark your windows with the price when you are trying to sell your car on the triangles marking the tread to sidewall transition on the tire. I raised pressure until I was running on the treads and not the sidewall. I had to go up around 40 psi on the run flats to keep them off the shoulder. I haven't run the PSS at the autocross yet but hope to this fall. I would not go lower on pressure based upon the softer sidewalls. I may go up.

If you run 32 psi I can see why you had a problem. But why do that? A more scientific test is to measure tread temperatures but I don't have the equipment for that. A bottle of marking fluid is only a couple bucks. Why not figure out the right pressure before driving 10/10ths?