2009 GMC Acadia Owner's Manual - Page 337

Service and Appearance Care 5-51 { 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 5-66. Make sure the spare tire, if the vehicle has one, 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 5-76. When It Is Time for New Tires Various factors, such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions influence when you need new tires. You need new tires if any of the following statements are true: • 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 to show cord or fabric. • The tire has a bump, bulge, or split. • The tire has a puncture, cut, or other damage that cannot be repaired well because of the size or location of the damage. The rubber in tires degrades over time, even if they are not being used. This is also true for the spare tire, if the vehicle has one. Multiple conditions affect how fast this aging takes place, including temperatures, loading conditions, and inflation pressure maintenance. One way to tell when it is time for new tires is to check the treadwear indicators, which will appear when the tires have only 1/16 inch (1.6 mm) or less of tread remaining.