2004 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 478

Buying New Tires To find out what kind and size of tires you need, look at the Certification/Tire label or the Tire and Loading Information label. See Loading Your Vehicle on page 4-57, for more information about these labels and where they can be found on your vehicle. The tires installed on your vehicle when it was new had a Tire Performance Criteria Specifications (TPC Spec) number on each tire's sidewall. When you get new tires, GM recommends that you get tires with that same TPC Spec number. That way your vehicle will continue to have tires that are designed to give proper endurance, handling, speed rating, load range, traction, ride, tire pressure monitoring system performance and other things during normal service on your vehicle. If your tires have an all-season tread design, the TPC number will be followed by an "MS" (for mud and snow). When ever you replace your 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 or radial) as your original tires. {CAUTION: Mixing tires could cause you to lose control while driving. If you mix tires of different sizes or types (radial and bias-belted tires), the vehicle may not handle properly, and you could have a crash. Using tires of different sizes may also cause damage to your vehicle. Be sure to use the same size and type tires on all wheels. Your vehicle may be equipped with a different size spare than the road tires (those originally installed on your vehicle). When new, your vehicle included a spare tire and wheel assembly with a similar overall diameter as your vehicle's road tires and wheels, so it is all right to drive on it. Because this spare was developed for use on your vehicle, it will not affect vehicle handling. 5-86