2011 Chevrolet Volt Owner's Manual - Page 428

10-62 Vehicle Care Lightly coat the center of the wheel hub with wheel bearing grease after a wheel change or tire rotation to prevent corrosion or rust build-up. Do not get grease on the flat wheel mounting surface or on the wheel nuts or bolts. Check that all wheel nuts are properly tightened. See "Wheel Nut Torque" under Capacities and Specifications on page 12‑2. { WARNING Rust or dirt on a wheel, or on the parts to which it is fastened, can make wheel nuts become loose after a time. The wheel could come off and cause a crash. When changing a wheel, remove any rust or dirt from places where the wheel attaches to the vehicle. In an emergency, a cloth or a paper towel can be used, however, use a scraper or wire brush to remove all rust or dirt. When It Is Time for New Tires Factors, such as maintenance, temperatures, driving speeds, vehicle loading, and road conditions affect the wear rate of the tires. Treadwear indicators are one way to tell when it is time for new tires. Treadwear indicators appear when the tires have only 1.6 mm (1/16 in) or less of tread remaining. See Tire Inspection on page 10‑61 and Tire Rotation on page 10‑61 for additional information.