DETROIT—Tires as "works of art"?
You may not think of them as such, but to a true tire aficionado, some of the rubber that shows up on concept vehicles could be considered real Michelangelos.
Consider Goodyear's Aquatred tires, designed as a concept in the early 1980s. Monikered "the baby butt tires" because of the groove running perfectly down their middle, they were carved by hand initially.
Or a close-up look at the Goodyear tires on the Batmobile in the latest Batman movie revealed a truly one-of-a-kind design—bats and all.
Whether development tires or concept tires, early prototypes are hand-carved by tradesmen using induction-heated knives. Each tire takes about 24 hours to create.
Although Continental Tire North America Inc. produces some concepts now, most in North America are supplied by Michelin North America Inc. and Goodyear, said Steve Lash, manager of concept development and innovation at Greenville, S.C.-based Michelin.
The people who carve the tires are "craftsmen—artisans," Mr. Lash said. "Every one of those tires has to look exactly the same."
How do you teach such an art?
"One groove at a time," said William Egan, chief engineer of advanced original equipment product design at Goodyear.
Hand carving tires actually began for economic reasons. Rather than casting a treaded mold at a cost of $60,000 to $80,000, tire makers often use hand carving, Mr. Egan said.
Treaded molds are four to five times more expensive than smooth molds, and because tire development ranges from one to three years, several molds could be needed.
But sometimes the laws of design won't accommodate the carving of a tire; it has to be molded. "In carving, you can only take away mass; you can't add it," Mr. Lash said.
Goodyear was the first tire maker to begin offering concept tires to vehicle makers in 1984 with two designs. In 1991, it produced 26 new concepts, and by 1995, 50 individual designs. Since then, demand for new tire concepts has progressively decreased; this year, Goodyear developed only 27.
"Concepts and prototypes dropped back to 23 when all of the auto companies pared back and we started getting competition," Mr. Egan said. "For many years, nobody did it but us."
Competition for Goodyear got particularly heavy in the mid-1990s when Michelin began producing its own concept tires.
Prior to Michelin's acquisition of Uniroyal/Goodrich in 1990, the division was producing concept tires in small numbers. Around 1994, Michelin itself started getting involved "in a big way," Mr. Lash said.
While Goodyear outsources about 95 percent of the carving of its concept and development tires to several Akron-based mold model shops, Michelin does all of its tire design and carving in-house.
"These concept cars are relatively secret, and we wouldn't farm that out to anybody," Mr. Lash said.
Michelin and Goodyear both said concepts are a way to pursue new OE relationships.
"Goodyear has traditionally had Chrysler locked up, but we've made some inroads there a little bit," Mr. Lash said.
Michelin's Pax tires, size 22 inch by 9 inch, were part of the package on the silver Jeep Willys concept unveiled at the 2001 North American International Auto Show, held Jan. 8-21 in Detroit. The gray tires with green sidewall accents perfectly suited the silver armored dune buggy while demonstrating Michelin's venture into colored tire technology.
Neither Goodyear nor Michelin passes on the $1,000-per-tire cost of concepts to the auto makers. "We get a lot out of just being on the vehicle. We get to learn different trends," Mr. Lash said.
"This isn't business for us," Mr. Egan said. "We're in there and talking to the people, working on these vehicles that could turn into a real production vehicle."
Tire makers retain the rights to their tread designs, usually patenting them. But the original concept tires become a permanent part of concept vehicles, Mr. Egan added.
Vehicle themes dictate tire design. During the recent show, automotive interiors supplier Johnson Controls Inc. revamped a van to show off its use of factory-installed Legos boards and other options catering to children and young families. The van included BFGoodrich concept tires with a chunky, Lego-looking tread for added impact.
Goodyear supplied concepts with tread resembling rippling sand for General Motors Corp.'s Chevy Borrego, which boasts "the agility of a rally car and the influence of Baja racers." It also supplied block-patterned tread tires for GMC's squared-off Terracross.
When it comes to concept tires, car makers are more concerned with aesthetics than performance, the tire makers said. "Snazzy tires generate initial interest in concept vehicles," Mr. Egan said.
Most concept tires and rims are made in sizes not yet approved by the Tire and Rim Association, sometimes getting as large as 23 inches in diameter. They are a sign of coming trends, the tire makers said.