1998 Cadillac DeVille Owner's Manual - Page 331

When It's Time for New Tires One way to tell when it's time for new tires is to check the treadwear indicators, which will appear when your tires have only 1/16 inch (1.6 mm) or less of tread remaining. The tire has a bump, bulge or split. The tire has a puncture, cutor other damage that of can't be repaired well because the sizeor location of the damage. Buying New Tires To find out what kind and size tires you need, look at of the Tire-Loading Information label. The tires installed on your vehicle when it was new had a Tire Performance Criteria Specification (TPC Spec) number on each tire's sidewall. When you get new tires, Spec get ones with that same TPC number. That way your vehicle will continue to have tires that are designed to give proper endurance, handling, speed rating, traction, ride and other things during normal service on your vehicle.If your tires havean all-season tread design, the TPC number will be followed by"MS" an (for mud and snow). You need a new tire if any of the following statements are true: You can see the indicators at three or more places around the tire. You can see cord or fabric showing through the tire's rubber. The tread or sidewall is cracked, cut or snaggea deep enough to show cord or fabric. 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. 6-44