Burning rubber, burning money: extending tire life can add thousands to the bottom line per truck and needn't cost a penny. Here are the top 10 ways to get more miles from your rubber

Canadian Forest Industries, Mar 2004

Today's tires are tough - almost too tough. They can take an enormous amount of abuse and still survive. But according to tire experts, neglecting tires can be quite costly.

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"Paying attention to tires in 10 key areas can add thousands of dollars annually to a truck operator's bottom line," says Terry Waibel, engineering manager for Goodyear Commercial Tires. "This isn't rocket science. It's just a set of basic tire maintenance procedures that are easy to follow with organization and discipline. Following these procedures will lower your per-mile tire costs through extended tread life, fewer premature removals, and better retreadability."

1. Determine proper inflation levels for your application

The biggest influence on tire life is inflation pressure. At normal speeds, running tires at 20% under recommended pressure reduces tire mileage by 16% and fuel mileage by 2%. Tires are designed to run at specific pressures based on the total load. To determine the correct air pressure for your tires, gather information on your actual axle loads and refer to tire load charts. Standard load charts are available at www.goodyear.com/truck. If you drive at higher or lower speeds, use the listed formulas to make the adjustments. In general, pressures need to be higher the faster you drive.

2. Establish a good inflation maintenance program

Tire pressure is difficult to maintain because tires naturally lose air. The leakage can occur through valve caps or through small punctures. To stay on top of "normal" leakage and watch for any rapid leaks, tires should ideally be checked once a week by drivers or mechanics. That can be tough if your trucks aren't in the shop at least once a week, or if your drivers are reluctant to comply. But there are ways to promote frequent checks. A growing number of fleets are using flow-through valve caps that make it easier to check pressure and add air without removing the valve cap. Other fleets give drivers an incentive to check pressures by conducting random checks on trucks, and rewarding drivers if the pressures are correct. Note that changes in ambient temperature will affect tire pressures. For every 10-degree F decrease in temperature, the pressure will drop 2 psi. So, during the colder months of the year, tires will need to be checked and inflated more often.

3. Reduce your top speeds

High speeds generate more heat and accelerate tire wear. Goodyear data show that increasing highway speeds to 75 mph from 55 mph can reduce total tread mileage by 20% or more. So a tire that would have provided 250,000 miles in tread life at 55 mph will net only 200,000 miles per tread if driven at 75 mph. The drop is quite consistent as speed increases. That 250,000-mile tread drops to 237,500 miles at 60 mph; 225,000 miles at 65 mph; and 212,500 miles at 70 mph. There's an added bonus for slowing down: Fuel economy tests have shown fuel usage increases 0.1 mpg for every mph over 55 mph.

4. Keep vehicles properly aligned

Irregular wear is most commonly caused by poor vehicle alignment. It's simple physics. If tires are not running straight ahead, accelerated tread wear occurs on parts of the tire. For example, steer axle toe-out will cause excessive wear on the inside of both tires while toe-in will cause wear on the outside shoulders of the tires. Ideally, most steer tires should have a small amount of toe-in. To maintain this, as well as stay on top of other types of irregular wear, the vehicle should be aligned regularly.

Starting a serious alignment program after having none can increase tire mileage by as much as 30%. While the focus has traditionally been on front end alignment, drive axle and trailer axle positioning can also have a significant impact. Fleet experience has shown that correct alignment of drive and trailer axles can extend total tire mileage by 25% as well as improve fuel mileage 0.5 to 1.0 mpg. More information on effective alignment schedules is available in Guidelines for Total Vehicle Alignment from the Technology and Maintenance Council. TMC also offers information on the causes of irregular wear in its Radial Tire Conditions Analysis Guide. Both publications are available online at www.truckline.com/store.

5. Mount tires correctly

The rounder or more concentric the tire, the better it will wear. To keep tire run out to a minimum, they should always be mounted on the wheel correctly. Ideally, the tires should be match-mounted to the wheel. Wheels are usually marked to show the low spot and tires are marked to show their high spot. How the high spot is marked will vary from one tire to another. Check with the tire manufacturer to see how they mark their tires. "The idea is to take the high spot of the tire and match it to the low spot of the wheel," Goodyear's Waibel says. "If you mount properly, you don't really need to balance the tire."

6. Learn to "read" tires

Drivers typically don't check tread wear unless they are having ride problems or the truck is pulling one way or another. By then, it's often too late to prevent premature wear. Regular inspections of tires can provide a lot of useful information and catch wear trends before they have done too much damage. Problems can be diagnosed by visual inspection or by running a hand over the tread and feeling for abnormalities. Items to check for include distortion in the tread, feathering, or cupping. If corrected early enough, bad wear patterns can be countered and tire life can be extended. "Rib edge feathering is a good early indicator of misalignment," Waibel says. "At the first sign of it, the vehicle should go in for an alignment." While a person is feeling the tread, the entire tire should also be inspected for such safety-related damage as cuts, cracks, blisters, or bulges. If the damage is severe enough, the tire will need to be removed.