Rethinking retreads

| December 12, 2008

If inflation maintenance is driving you batty, look at a tire inflation system. Many will pay for themselves in less than two years because of savings in emergency calls, the manufacturers say.

They also save fuel. Al Cohn of Pressure Systems International, which makes the Meritor Tire Inflation System, reports that fuel economy drops by 1 percent if pressure is 10 percent low, 2 percent if 20 percent low, and more than 4 percent if 30 percent low.

Tire casings also can be injured by running mismatched tires in dual positions. The tire with the larger diameter ends up overloaded, while the smaller one eventually experiences scrubbing of the tread. When both tires overheat, energy and gobs of fuel are wasted.

Significant misalignment, a critical issue on 18-wheelers because of the length of the trailer, often has a similar effect because the tread actually scrubs sideways, Brodsky says.

A helpful way to preserve a casing is to make sure the tread never wears too thin – below 4/32 on steers and 2/32 on the other tires. This also will keep DOT inspectors happy. Several tire experts, however, advocate retreading well before reaching those limits. Demianenko thinks observing at least 3/32 as an overall limit pays off in added casing protection.

One obvious reason a little extra rubber goes a long way is that the typical puncture is caused by objects, such as carpet tacks, that would never reach the casing if the tread were thick enough. Preventing punctures not only eliminates leaks but protects the casing from the damage that would occur from running underinflated until the leak was detected.

If the casing is penetrated, you still can save it most of the time – if you take it to the right tire repair shop that won’t just plug it and call it done. A high-quality repair means the tire is removed from the wheel and repaired with a vulcanizing process that seals the inner liner. Plugs just seal in moisture; they often result in rusted cords and catastrophic failure. “I’m dead set against plugs,” Brodsky says. “Fix the casing from the inside.”

A high-quality casing, properly maintained and properly repaired as needed, is good for two more cycles after its first life. Retreads are legal on steer tires, though it’s more common to run virgin tires there and then retread them at other positions. Drive tires often will be retreaded once or even twice, then switched to the trailer for one more cycle.

Take care of the casing and pick the right retreader, and you’ll greatly enhance your chances of cutting tire costs to the bone without risking an expensive and dangerous failure.

As a group, retreads have one advantage over new tires other than cost. The pre-cure process, in which tread is molded by itself and later vulcanized to the tire, has enabled the creation of a bonanza of new tread designs you can get only on retreads.

In fact, you can select among application-specific tread designs that last longer because they are ideally configured for certain uses. “Choosing the ideal tread pattern – rib-or lug-type tread design – depends on the type of operation and traction requirements, as well as other similar factors,” says Glenn Stockstill of Michelin.

This is one area that separates responsible retreaders from the others, says Harvey Brodsky of the Tire Retread Information Bureau. “Don’t just let them pick up your tires,” he says. “Spend time with the retreader so you can learn something about tread design and you can tell them about how you use your vehicles. Deal only with people who know what you are doing in your operation.”

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