1993 Buick Regal Owner's Manual - Page 245

A When It's Time for New Tires CAW'ON b wav to tell when it's One r' Rust or dirt on a wheel, or on the parts to which it i fastened, can make wheelnuts become s loose after a time. The wheel could come off a-" cause an accident. When you change a wheel, remove any rust or dirt fromplaces where the wheel attaches to the vehicle. In an emergency, you can use a cloth or a papertowel to do this; but be sure to use a scraper or wire brush later, if you need to, to get all the rust or dirt off. (See i the Index.) n "nhanging a Flat I I 0 time for new tires is to check the treadwear indicators, which will appear when your tires have only 2/32 inch (1.6 mm) or less of tread remaining. TREAD WEAR INDICATORS I You need a new tire if You can see the indicators at three 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 to show cord or fabric. The tire has a bump, bulge or split. 243