i think someone ought to post what the speed rateing stands for because i dont think that everyone completely understands the rate scale....z rated tires are designed to withstand a constant time(4-5hrs) at high speeds (130+mph)
"S" rated tires are supposed to handle a constant time(4-5hrs) at speeds of 100 to 130... thats a general (give or take a couple mph) statement of speed rateing from a master mechanic at a ford dealership i work at.
