Maintenance 129 Tire Inflation and Wear DANGER WARNING Before checking the tires, set the parking brakes, place the transmission in neutral and block the wheels. Failure to do so can result in unexpected vehicle movement and can cause serious personal injury or death. Check tire pressure when the tire is cool. Never bleed the air from hot tires. Increased tire pressure measured in a hot tire is normal. Low pressures may cause side wall flexing, resulting in increased heat, leading to tire failure and vehicle accident. Measure the tread depth. The depth should not be less than 6/32 in. (4.8 mm) on front tires and not less than 2/32 in. (1.6 mm) on drive tires. Note:
Most premium steer tires start with 18/32 in. (14.2 mm) tread depth when new. Usually remove steer tires at 6/32 in (4.8 mm). Drive tires should be removed at not less than 2/32 in. (1.58 mm) It is important to have the wheels correctly aligned. Check for uneven tire wear frequently. Uneven tire wear is a sign of wheels out of alignment. Refer to page 158 for examples of typical tire wear. W7000773 WARNING DO NOT operate the vehicle with under-inflated tires. Always keep your tires inflated to the manufacturer’s recommendation. Increased flexing in the tire sidewall produces heat. The heat can build to the point of blowing the tire out causing an accident.
Remove stones lodged in ribs or in between double-mounted wheels. Check the tire pressure and leak-test the valve stems. W7001270