1996 GMC Savana Van Owner's Manual - Page 269

Dual Tire Operation When the vehicle is new, or whenever a wheel, wheel bolt or wheel nut is replaced, check the wheel nut torque after 100, 1,000and 6,000 miles ( 160, 1 600 and 10 000 km) of driving. For proper torque, see"Wheel Nut Torque" in the Index. The outer tire on a dual wheel setup generally wears faster than the inner tire. Your tires will wear more evenly and last longer if you rotate the tires periodically. If you're going to be doing a lot of driving on high-crown roads, you can reduce tire wear by adding 5 psi (35 kPa) to the tire pressure in the outer tires. Be sure toreturn to the recommended pressures when no longer drivingunder those conditions. See"Changing a Flat Tire" in the Index for more information. Buying New Tires To find out what kind and size of tires you need, look at the Certification/Tire label. The tires installed on your vehicle when it was new had a Tire Performance Criteria Specification (TPC Spec) number on each tire's sidewall. When you get new tires, get ones with that same TPC Spec number. That way your vehicle will continue tohave tires that are designed to give proper endurance, handling, speed rating, traction, ride 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). A CAUTION: If you operate your vehicle witha tire that is badly underinflated, the tire can overheat. An overheated tirecan lose air suddenly or catch fire. You or others could be injured. Be sure all tires (including the spare) are properly inflated. If you ever 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.