Extending Tire Life
BY DAVID KOLMAN
Following a set of basic tire maintenance procedures will lower per-mile tire costs through extended tread life, fewer premature tire removals and better retreadability, advises the Goodyear Tire & Rubber Co. These procedures include:
Determine proper inflation levels for your application. The biggest influence on tire life is inflation pressure because tires are designed to run at specific pressures based on the total load. (This information can be found in tire load charts, available from tire manufacturers.) At normal speeds, running tires at 20 percent under recommended inflation pressure reduces tire mileage by 16 percent and fuel mileage by 2 percent.
Establish a good inflation maintenance program. Tire pressure is difficult to maintain because tires naturally lose air over time and leakage can occur through valve caps or through small punctures. Air pressure should be checked at least once a week using a calibrated air gauge.
Protect sidewalls from curb damage. In-city driving and pick-up-and-delivery routes present many opportunities for potential sidewall damage. Alert drivers to the importance of avoiding sidewall impact and encourage drivers and technicians to inspect tires regularly for sidewall wear and damage.
Keep vehicles properly aligned. Irregular tire wear is most commonly caused by poor vehicle alignment. If tires are not running straight ahead, accelerated tread wear occurs.
Mount tires correctly. The rounder or more concentric the tire, the better it will wear. To keep tire runout — a condition in which a tire or rim is out of round when rolling — to a minimum, tires should always be mounted correctly on the wheel. Ideally, the tires should be match-mounted to the wheel. Match mounting tires on wheels is a process where a tire’s installed position on the wheel is specifically selected to help minimize the final combination’s forces and/or imbalance that can affect a vehicle’s ride quality.
Learn to “read” tires. Regular inspections of tires — both visually and by running a hand over the tread and feeling for abnormalities — can provide a lot of useful information and catch wear trends before they have done too much damage. If corrected early enough, bad wear patterns can be countered and tire life extended.
Rotate tires. Tire rotation promotes even tread wear and can net a lot of extra miles in tread life. Drive tires should be rotated between forward and back positions at least once to even out wear. Rear tires of a tandem axle typically will wear more quickly than the forward positions. Some drive tires will also develop heel and toe wear. This is a condition where the tread on the leading edge of the tire is round, like the heel of a foot, and the tread on the trailing edge is pointed, like a toe. Heel and toe wear can be evened out by reversing the drive tires direction.
Replace tires with matching ones. For optimum tread wear, tires need to be as alike as possible across the same positions. If a tire must be pulled due to irregular wear or a road hazard, it should be replaced with a tire that matches the existing one. On dual assemblies, the outside diameters and tread depths should be as close as possible. A good rule of thumb is no more than 2/32-inch tread depth difference between duals. It’s also best to have the same tread design on both positions of an axle.
Check and replace worn wheel and suspension components. These can be the hidden enemies of tire life. A wheel bearing that is not properly torqued can cause irregular tire wear. Worn shock absorbers can create depression wear on treads and an early trip to the retreader or scrap pile. To prevent irregular tire wear, replace shock absorbers and other suspension components on a set schedule rather than waiting until they fail.
Keep good tire records and use the data wisely. Because every fleet is different, there are no hard and fast formulas for tire management. In fact, copying another fleet’s practices may do more harm than good. To manage tires most efficiently, regular collection and analysis of data on tires — such as tire inflation pressures, wear trends and tire mileage at removal — is critical. BI