Pretrip Inspection and Daily Maintenance caps are on every tire and that they are screwed on finger-tight. Inflate the tires to the applicable pressures, if needed. Overinflation gives the treaded surface of the tire a convex shape ( Fig. 9.6 ). This causes extreme tire wear in the middle part of the tire since this section is primarily in contact with the road. Underinflation gives the tread surface a con- cave shape ( Fig. 9.6 ). This causes exces- sive tire wear on the outer edges of the tire since they are primarily in contact with the road.
37.2 If a tire has been run flat or underinflated, check the wheel for proper lockring and side ring seating, and possible wheel, rim, or tire damage before adding air. 37.3 Moisture inside a tire can result in body ply separation or a sidewall rupture. During tire inflation, compressed air reservoirs and lines must be kept dry. Use well-maintained inline moisture traps and service them regularly. f400061 11/03/94 pressure loss of 4 psi (28 kPa) or more in a tire may indicate damage and the tire should be inspected and repaired or replaced. Fig. 9.5, Check Tire Pressure 37.4 Inspect the tires for bulges, cracks, cuts, or penetrations.
A tire pressure check will assist in uncovering hidden damage. A weekly 37.5 Tires should also be inspected for oil con- tamination. Fuel oil, gasoline, and other pe- troleum derivatives, if allowed to contact the tires, will soften the rubber and destroy the tire. 9.19