1998 Pontiac Bonneville Owner's Manual - Page 295

When It's Time for New Tires One way to tellwhen 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. Buying New Tires To find out what kind and size tires you need, look at of the Tire-Loading Information label. The tires installed your vehicle whenit was new had on a Tire Performance Criteria Specification (TPC Spec) number on each tire's sidewall. When you new tires, get get ones with that same TPC Spec number.That way your vehicle will continue to have that are designed tires 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 followed by "MS" an (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. You need anew tire if any of the following statements are true: 0 0 0 0 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 snagged deep enough to show cord or fabric. The tire has a bump, bulge or split. The tire has a puncture, cut or other damage that can't be repaired well because of the size or location of the damage. 6-44