When It Is Time for New TiresOne way to tell when it’stime for new tires is tocheck the treadwearindicators, which willappear when your tireshave only 1/16 inch(1.6 mm) or less of treadremaining. Somecommercial truck tires maynot have treadwearindicators.You need a new tire if any of the following statementsare true:• You can see the indicators at three or more placesaround the tire.• You can see cord or fabric showing through thetire’s rubber.• The tread or sidewall is cracked, cut or snaggeddeep enough to show cord or fabric.• The tire has a bump, bulge or split.• The tire has a puncture, cut or other damage thatcan’t be repaired well because of the size orlocation of the damage.Buying New TiresTo find out what kind and size of tires you need, look atthe Certification/Tire label or the Tire and LoadingInformation label. SeeLoading Your Vehicle onpage 4-47, for more information about these labels andwhere they can be found on your vehicle.The tires installed on your vehicle when it wasnew had a Tire Performance Criteria Specifications(TPC Spec) number on each tire’s sidewall. When youget new tires, GM recommends that you get tireswith that same TPC Spec number. That way yourvehicle will continue to have tires that are designed togive proper endurance, handling, speed rating, loadrange, traction, ride, tire pressure monitoring systemperformance and other things during normal service onyour vehicle. If your tires have an all-season treaddesign, the TPC number will be followed by an “MS”(for mud and snow).5-76
