2008 Buick Enclave Owner's Manual - Page 365

When It Is Time for New Tires {CAUTION: Rust or dirt on a wheel, or on the parts to which it is fastened, can make wheel nuts become loose after time. The wheel could come off and cause an accident. When you change a wheel, remove any rust or dirt from places where the wheel attaches to the vehicle. In an emergency, you can use a cloth or a paper towel to do this; but be sure to use a scraper or wire brush later, if needed, to get all the rust or dirt off. See Changing a Flat Tire on page 5-73. Make sure the spare tire is stored securely. Push, pull, and then try to rotate or turn the tire. If it moves, tighten the cable. See Storing a Flat or Spare Tire and Tools on page 5-85. Various factors, such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions influence when you need new tires. One way to tell when it is 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. 5-65