If you're like most US motorists, you buy new tires for your car. One way to cut costs, however, is to recycle your worn, expensive tires and buy retreads.
To put it simply, retreads perform. During the past five years, drivers at the Bob Bondurant School of High Performance Driving at Sears Point International Raceway in northern California put more than 3 million tire miles on retreads.
''When the only thing between you and the road are the tires, Mr. Bondurant says, ''they have to be reliable. We teach police, corporate chauffeurs, and race-car drivers maximum car control: skid control, emergency racing procedures, heel and toe downshifting, and complete car feel.''
Bondurant has found that retreads do the job at far less cost than new tires.
The Bondurant school cars - Datsun ZXs - formerly ran 250 miles on one set of new tires. Now, by contrast, the same cars get 800 miles on Bandag performance retreads supplied by the Downey Tire Center in Santa Rosa, Calif. The Downey plant is the only one in the country that specializes in retreads for high-performance cars.
In 1978 Bandag received special permission to run retreads on an entry in Florida's 12-hour Sebring race. While the car finished fourth, the set of retreads lasted the full 12 hours of the race. Other drivers had to change their soft race tires four times.
''Retreads conserve energy,'' says John Downey, president of the business.
''It takes 71/2 gallons of crude oil to produce one new passenger tire,'' he adds. ''By re-using the casing, retreads use only 11/2 gallons.'' A retread costs approximately 50 to 60 percent of what a new tire costs.
Explaining the process he uses in his shop, Mr. Downey says, ''There are two ways to retread a tire: the hot process and the cold process.
''In the hot process, after the tread is removed, uncured rubber stock is wrapped around the tire and inserted into a hot mold with a design to cure out. The cold, or precure, process does not use molds.''
Simply, the tread is precured separately before it is bonded to the casing.
The precure process was originated by German Field Marshal Erwin Rommel during World War II in North Africa, using the hot sand of the Sahara to cure the rubber.
Many years later Roy Carver, a pump manufacturer from Muscatine, Iowa, chanced upon the precure process during a business trip to West Germany. In 1959 he bought the North American rights, which specified that he retain the German name ''Bandag.''
Normally, passenger tires are retreaded only once; truck tires are retreaded five or six times. Airlines also use retreads on their super jets.
Retreads create a saving for taxpayers in northern California, where school-district buses in Sonoma County, ambulance and public transit in Santa Rosa, and some Golden Gate Transit buses in Marin County are running on Downey retreads.
About 25 percent of all the cars on the road in the US use retreads.