Pushing to catch up with aftermarket rivals, General Motors Corp. will add 36 factory-approved plus-sized tire and wheel sets within the next year for sale at car dealerships.
GM will launch five tire-wheel combinations this fall for full-sized sport-utility vehicles and pickups, giving it 15 20-inch sets for its full-sized trucks.
Vehicles include the Chevrolet Silverado, Tahoe, Suburban and Avalanche; GMC Sierra and Yukon; and Cadillac Escalade.
Retail prices for 20-inch tire-and-wheel sets range from $2,750 to $3,900, including installation, balancing and recalibrating equipment such as the speedometer and anti-lock brakes.
Nancy Philippart, executive director of accessories, said GM may approve 20-inch-plus wheels when it replaces the full-sized truck architecture for the 2007 model year.
``As we go to our next generation, we know that bigger is better,'' Ms. Philippart said. ``We're pushing to have a larger size.''
GM will add 11 tire-and-wheel sets this year for other vehicles, including mid-sized SUVs, the Chevrolet Corvette and Equinox sport wagon and several cars. Ms. Philippart said 20 more sets will debut by mid-2005.
The auto maker launched its first set of custom wheels and tires at last fall's Specialty Equipment Market Association (SEMA) show after issuing a warning in early 2003 urging car dealers not to sell aftermarket tire-and-wheel sets due, in part, to possible liability issues.
GM questioned the safety of tires and wheels that it had not tested, telling its dealers that such equipment would void warranties. The car maker said it would not defend product liability lawsuits arising from use of non-GM-approved wheels.
Dealers had said that GM was missing the booming custom wheel market, which offers fat profit margins.
Ms. Philippart said the company does extensive testing of tires and wheels to gauge their effect on handling and safety. Particularly with SUVs, she said, GM is concerned about raising the vehicle's center of gravity, which could increase the risk of rollovers.
But GM wants to satisfy customers and dealers, she added. Some local dealer marketing groups have put together custom packages of GM-approved wheels and other accessories, advertising them locally.
GM will encourage such initiatives, she said: ``You can envision hundreds of them happening around the country.''