2008 GMC Sierra 1500 Pickup Owner's Manual - Page 371

CAUTION: (Continued) • Overinflated tires are more likely to be cut, punctured, or broken by a sudden impact - such as when you hit a pothole. Keep tires at the recommended pressure. • Worn, old tires can cause accidents. If the tire's tread is badly worn, or if your vehicle's tires have been damaged, replace them. 20-Inch Tires If your vehicle has the optional 20-inch P275/55R20 size tires, they are classified as touring tires and are designed for on road use. The low-profile, wide tread design is not recommended for off-road driving. See Off-Road Driving on page 4-12, for additional information. Passenger (P-Metric) Tire Tire Sidewall Labeling Useful information about a tire is molded into the sidewall. The following illustrations are examples of a typical P-Metric and a LT-Metric tire sidewall. (A) Tire Size: The tire size code is a combination of letters and numbers used to define a particular tire's width, height, aspect ratio, construction type, and service description. See the "Tire Size" illustration later in this section for more detail. (B) TPC Spec (Tire Performance Criteria Specification): Original equipment tires designed to GM's specific tire performance criteria have a TPC specification code molded onto the sidewall. GM's TPC specifications meet or exceed all federal safety guidelines. 5-59