1998 GMC Jimmy Owner's Manual - Page 313

When It's Time for New Tires One way to tell when it's time fornew tires is to check the treadwear indicators, which will appear when your tires have only 1/16 inch (1.6 1 1 1 ) 111 or less of tread remaining. 0 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 orlocation of the damage. Buying New Tires To find out what kind andsize of tires you need, look at the Certificatioflire 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, get ones with that same TPC Specnumber. That way your vehicle will continue to have tires are designed that to give proper endurance, handling, speed rating, traction, rideand other things during normal service on your vehicle. If your tires have an all-season tread design, theTPC number will be followed by an "MS" (for mud and snow). If you ever replaceyour 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 orradial) as your original tires. You need a new tire if any of the following statements are true: 0 You can see the indicators three or more places at around the tire. You can see cord or fabric showing through the tire's rubber. 0 0 The tread or sidewall is cracked, cut orsnagged deep enough to show cord or fabric. 6-44