1994 Buick Roadmaster Owner's Manual - Page 261

The tire has a puncture, cut, or other damage that can't be repaired well because the size or location of of the damage. Buying New Tires To find out what kind and size tires you need, lookat of the Tire-Loading Information label. The tires installedon your vehicle when was new had it a Tire Performance Criteria Specification (TPC Spec) number on each tire's sidewall:When you get newtires, get ones with that same TPC Spec number. That way, your vehicle will continue have tires that are designed to to give proper endurance, handling, speed rating, traction, ride and other things during normal service on your vehicle. If your tires have an all-season tread design, the TPC number will be followeda "MS" by (for mudand snow). If you ever replace your tires with those not having a TPC Spec number, make sure theyare the same size, load range, speed rating and construction type (bias, bias-belted or radial) as your original tires. Uniform Tire Quality Grading The following information relates to the system developed by the United States National Highway by Traffic Safety Administration which grades tires treadwear, traction and temperature performance. (This applies only to vehicles sold the United States.) in Treadwear The treadwear grade is comparative rating based on a the wear rateof the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one anda half