1998 Chevrolet Astro Owner's Manual - Page 307

Don't include the compact sparetire in your tire rotation. After the tires have been rotated, adjust thefront and rear inflation pressures as shown on the Certificationire label. Make certain that all wheel nuts are properly tightened. See "WheelNut Torque" in the Index. When It's Time for New Tires One way to tell when it's time fornew tires is to check the treadwear indicators, which will appear when your tires have only 1/16 inch (1.6 mm) or less of tread remaining. Rust or dirt onwheel, or on the parts to which a it is fastened, can make wheel nuts becomeloose after a time. Thewheel could comeoff and cause an accident. When change a wheel, remove you any rust or dirt from places where thewheel attaches to the vehicle. In an emergency, you can towel to do this; but be use a cloth or a paper sure touse a scraper orwire brush later, if you need to, to all the rust or dirt (See get off. "Changing a Flat Tire" in the Index.) I You need a new tire if any of the following statements are true: 0 You can see theindicators at three or more places around the tire. 0 YOU can see cord or fabric showing through the tire's rubber. The tread or sidewall is cracked, cut orsnagged deep enough to show cord or fabric. 0 The tire has a bump, bulge orsplit. 0 The tire has a puncture, cut or other damage that can't be repaired well because of the size or location of the damage. 6-45