Tire speed ratings basically tell you how fast you can go before your tires turn into shrapnel. Your everyday grocery-getters can get away with, say, inexpensive S-rated tires that will hold together ...
Tire treadwear ratings, also known as Uniform Tire Quality Grading (UTQG), were developed by the National Highway Traffic Safety Administration (NHTSA) and the U.S. Department of Transportation (DOT).