Originally Posted by kotik
I'll start off by saying i live in Germany...
I ordered a set of snow tires from TireRack and they are rated up to 149mph (pirrelli i believe). Does that mean I can cruise at 149mph? What would be safe cruising speed for those tires? What happens if I go faster?
Also, what tire pressure should i run in those tires? I frequent north of 100mph.
The speed rating is a tire's maximum sustained speed assuming proper tire inflation, no damage and/or repair has been done to the tire (e.g., no plug or patch). If you exceed the speed rating of the tire then you risk the possibility of a tire failure - related to centripetal acceleration of the tire and excessive heat build up. It is not recommended to exceed the tire speed rating.
I've never used those tires but, if the tire can handle it, one option is to start with the M3 OEM tire pressures for speeds exceeding 100 mph and adjusted for vehicle load - however, these pressures are for summer tires, not winter tires so they may not apply. You could also contact Pirelli to see what pressures they recommend for > 100 mph.