1998 Buick Century Owner's Manual - Page 301

When rotatingyour tires, always use the correctrotation pattern shown here. Don't include the compact spare tire your in tire rotation. After the tires have been rotated, adjust the front and rear inflation pressures shown on the Tire-Loading as Information label. Make certain that wheel nuts are all properly tightened. See "Wheel Torque" in Nut the Index. When It's Time New Tires for 3 1 One way to tell whenit's time for new 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 a wheel, or on the parts to which on it is fastened, can makewheel nuts become loose after a time. The wheel could come and cause off an accident. When you change a wheel, remove any rust or dirt from places wherethe wheel attaches to the vehicle. In anemergency, youcan use a cloth or a paper towel to dothis; but be sure touse a scraper orwire brush later, if you need to, to get all the rust dirtoff. (See or "Changing a Flat Tire" in theIndex.) You need a new tire if any of the followingstatements are true: 0 You can see the indicators at three or more places around the tire. You can see cord or fabric showing through the tire's rubber. The tread or sidewall is cracked, cut or snagged deep enough toshow cord or fabric. The tire has a bump, bulge or split. 0 0 0 6-41