1996 Buick Regal Owner's Manual - Page 259

When rotating your tires, always use the correct rotation pattern shown here. Don't include the compact spare tire in your tire rotation. After the tires have been rotated, adjust the front and rear inflation pressures as shown the Tire-Loading on Information label. Make certain that all wheel are nuts properly tightened. See "Wheel Nut Torque" in the Index. When It's Time for New Tires One way to tell when it's time fornew tires isto check the treadwear indicators, whichwill appear when your tires have only 1/16 inch (1.6 mm) or less of tread remaining. Rust or dirt on a wheel, or on the partsto which it is fastened, can make wheel nuts become loose after a time. The,wheel could come and cause off an accident. When you change a wheel, remove any rust ordirt from.places where the wheel attaches to the vehicle. In anemergency, you can use a cloth or a paper towel to do this; but be sure to a scraper or use wire brush later, if you need to, to get all the rust or dirt (See off. "Changing a Flat Tire"in the Index.) You,need a new tire if any of the followingstatements are true: 0 You can seethe indicators atthree or moreplaces around the tire. You can see cord fabric showing through the or tire's rubber. The tread or sidewall is cracked, cut or snagged deep enough to show cord or fabric. The tire has abump, bulge or split. 0 0 0 6-37