Tires Delay Michigan 500 One Week

A dispute over Goodyear radial tires Saturday forced postponement of today’s CART Michigan 500 Indy-car race at Michigan International Speedway until next Sunday.

Announcement of the schedule change followed a meeting between CART officials, track management and representatives of the Goodyear Tire & Rubber Co. racing division.

The meeting was called after two morning crashes, one involving provisional pole-sitter Bobby Rahal in his March-Cosworth.

Rahal--who will retain the pole--was not injured in the crash that occurred when the right front tire on his car was punctured on Turn 2 of the two-mile oval speedway. Rahal’s car was extensively damaged after it hit the wall.

The other accident occurred minutes later when the right front tire blew on Roberto Guerrero’s March-Cosworth and sent him into a wall. Officials said Guerrero also escaped serious injuries.

Dave Hederich, a spokesman for Goodyear, said there is speculation that the accidents may have been caused by new radial tires. The Michigan 500 was to have been the first race on a super speedway to use radial tires.

Hederich said all drivers will now switch to bias-ply tires rather than the body-ply radials.

“Body-ply radials are more susceptible to punctures,” Hederich said. “The body ply is circumferential around the tire and is at a 90-degree angle to the race surface. The bias ply has a diagonal ply and is at a 45-degree angle.

“The drivers told us they liked the radials. But in a joint decision and to ensure the safety of every driver, we decided we’d go back to the tires that have been used here in the past.”

The tires are due to arrive by Tuesday. The track will open for additional practice Friday, with the final qualifying sessions for remaining positions a day later.

NBC-TV said it will show a tape of the 1984 Michigan 500 today but will not televise next Sunday’s race.