Tire-related costs are the single largest maintenance expenditure for commercial motor vehicle (CMV) fleet operators, and represent one of the two highest costs of running a truck, second only to fuel! Improper tire maintenance is also a major cause of tire failure and blowouts.
Many of these costs can be averted by ensuring that drivers always inspect and maintain their tires. Properly kept tires deliver more mileage, reduce fuel costs and tire malfunctions, and increase safety and operational reliability. It will also save money and reduce driver downtime, along with out-of-service percentages that result from tire violations.
An accurate air pressure gauge is an essential as part of the pre-trip inspection. When various methods of measuring tire pressure were tested, it was determined that using a precise air gauge is the only way. It is nearly impossible to correctly estimate pressure by kicking or thumping a tire.
Tire dealers and trucks stops should have a master gauge, against which drivers can check the accuracy of their personal gauge. The gauge should be replaced if it is off by more than five pounds per square inch (psi), which can happen if it is dropped onto concrete just one time. Numerous tire pressure monitoring and automatic inflation systems tailored to CMVs are also available from vendors.
Pressure should be measured when tires are cold, or more than three hours after the vehicle was last driven. As a vehicle is driven, the tires get warmer causing air pressure within them to increase up to 15 psi. However, if the driver believes that a tire is underinflated while driving, the National Highway Traffic Safety Administration (NHTSA) recommends filling the tire to the proper cold inflation pressure indicated on the vehicle’s tire information placard or certification label. Although the tire will still be slightly underinflated, it is safer than continuing to drive on a significantly underinflated tire.
Because tires naturally lose air over time, CMV drivers should check all tires for correct air pressure every day. Drivers should also inspect tires for uneven wear patterns, cracks, bubbles, bumps, foreign objects and other signs of wear or trauma, and remove any foreign objects wedged into the tread.
If tire pressure is too low, drivers should note the difference between the measured tire pressure and the correct tire pressure and drive to the nearest service center to correct the difference. Then continue to monitor the tires for decreasing pressure.