2008 Pontiac G8 Owner's Manual - Page 240

9-56 Vehicle Service and Care You need new tires if any of the following statements are true: they degrade due to age. If you are unsure about the need to replace the tires as they get older, consult the tire manufacturer for more information. When It Is Time for New Tires Various factors, such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions influence when you need new tires. • 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. Buying New Tires GM has developed and matched specific tires for your vehicle. The original equipment tires installed on your vehicle, when it was new, were designed to meet General Motors Tire Performance Criteria Specification (TPC Spec) system rating. If you need replacement tires, GM strongly recommends that you get tires with the same TPC Spec rating. This way, your vehicle will continue to have tires that are designed to give the same performance and vehicle safety, during normal use, as the original tires. • 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 cannot be repaired well because of the size or location of the damage. The rubber in tires degrades over time, even if they are not being used. This is also true for the spare tire, if the vehicle has one. Multiple conditions affect how fast this aging takes place, including temperatures, loading conditions, and inflation pressure maintenance. With proper care and maintenance tires typically wear out before One way to tell when it is time for new tires is to check the treadwear indicators, which will appear when the tires have only 1/16 inch (1.6 mm) or less of tread remaining.