1993 Oldsmobile Silhouette Owner's Manual - Page 252

Sewice & Appearance Care Buying New Tires To find out what kind andsize of tires you need, look at the Certification/Tire label. The tires installed on your vehicle when it was new hada Tire Performance Criteria Specification (TPC Spec) number on each tire's sidewall. When you get new tires, get ones with that same TPC Spec number. That way, your vehicle will continue to have tires that are designed to giveproper endurance, handling, speed rating, traction, ride and other things during normal service on your vehicle. If your tires have an allseason tread design, the TPC number will be followedby a "MS" (for mud and snow). If you ever replace your tires with those not having a TPC Spec number, make sure they are the same size, load range, speed rating and construction type (bias, bias-belted or radial) as your original tires. Mixing tires could cause you to lose control while driving. If you mix tires of different sizes or types (radial and bias-belted tires), the vehicle may not handle properly, and you could have a crash. Be sure to use the same size and type tires on all four wheels. It's all right to drive with your compact spare, though. It was developed for useon your vehicle. Uniform Tire Quality Grading u The following information relates to the system developed by the United States National Highway Traffic Safety Administration which grades tires by treadwear, traction and temperature performance. (This applies only to vehicles sold in the United States.) 250