1997 Pontiac Firebird Owner's Manual - Page 298

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. 0 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. Buying New Tires To find out what kind and sizeof tires you need, look at the Tire-Loading Information label. The tires installed on yourvehicle when it was new had a Tire Performance Criteria Specification (TPC Spec) number on each tire's sidewall. When you get new tires, get ones with that same TPCSpec 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 anall-season tread design, the TPC number will be followed an "MS" by (for mud and snow). If you ever replace your tires with those not having a TPC Spec number, make surethey are the same size, load range, speed rating and construction type (bias, bias-belted or radial) as youroriginal tires. You need a new tire if any of the following statements are true: 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 cordor fabric. 0 0