2009 GMC Sierra 1500 Crew Cab Owner's Manual - Page 478

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 or commercial uses such as snow plowing. See Off-Road Driving on page 4-13 and Adding a Snow Plow or Similar Equipment on page 4-40 for additional information. Notice: If the vehicle has low-profile tires, they are more susceptible to damage from road hazards or curb impact than standard profile tires. Tire and/or wheel assembly damage can occur when coming into contact with road hazards like, potholes, or sharp edged objects, or when sliding into a curb. The vehicle warranty does not cover this type of damage. Keep tires set to the correct inflation pressure and, when possible avoid contact with curbs, potholes, and other road hazards. 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. Passenger (P-Metric) Tire (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. 5-68