Expert Blames Tire Defects on Many Factors
The Firestone tires that tore apart at high speeds, causing dozens of fatal accidents, lost their treads for a variety of engineering and usage reasons, according to the independent expert who released his report on the tires’ problems Friday.
In August, Bridgestone/Firestone Inc. recalled about 6.5 million tires, including all 15-inch ATX and ATX II tires and 15-inch Wilderness AT tires made at its Decatur, Ill., plant. The tire failures have been linked to at least 148 highway deaths in the United States and dozens more overseas. Most of the recalled tires were sold on Ford Explorer sport-utility vehicles.
Sanjay Govindjee’s report largely mirrored Firestone’s own probe released Dec. 19. Both said de-treading was caused by small cracks that spread between the tires and the steel belts around them.
“This cracking is influenced by a number of factors, including climate, design of the tire, manufacturing differences at Firestone’s Decatur plant and usage factors” such as overloading, Govindjee said in his 73-page report.
Critics immediately jumped on the report by the UC Berkeley associate professor of civil engineering, saying it adds little understanding of the recalled tires’ problems and fails to address the risks of tires that were not recalled and are still on trucks across the nation.
“Dr. Govindjee’s report tells us nothing we did not already know in that he is basically saying that the tires are failing more than they should be, that they are failing in hot weather climates, and that the failure rates appear to be related to a multi-factored problem,” said Tab Turner, an Arkansas attorney and leading critic of Ford Motor Co. and Firestone.
Govindjee stopped short of placing blame on the design of the Explorer, the country’s best-selling SUV. Explorers have been involved in a number of rollover accidents linked to tread separation.
Firestone has maintained that part of the problem is a design flaw in the Explorer that causes rollovers when tires fail. Ford has steadfastly maintained it is the tires’ fault.
“I didn’t really do an investigation of whether Firestone or Ford is to be blamed here,” Govindjee said in a conference call.
Turner said: “The most interesting finding . . . [is a conclusion] that the Decatur-made Wilderness tires have failure rates that are virtually identical to the other plants. Ford and Firestone can no longer ignore the fact that all of these tires, regardless of plant of origin, are bad tires.”
Turner was referring to Govindjee’s finding that warranty claims data showed the recalled Wilderness AT tires made in Decatur had a failure rate of 0.8 times that of an undisclosed “base rate,” compared with 0.7 times for recalled Wilderness ATs made in Wilson, N.C., and 0.8 times for those produced in Joliette, Canada.
That concedes “the rate at which customers brought their tires in for problems was essentially the same, whether the tires were made in Decatur, Joliette or Wilson,” said Joan Claybrook, president of consumer group Public Citizen. “This means that all Wilderness AT tires could crack and separate” regardless of where they were made and should be recalled, Claybrook said.
But Govindjee also said he found that tires made in Decatur had markedly weaker bonds than tires from Wilson and Joliette in the rubber between the steel belts and the tire. He could not pinpoint rea sons for the discrepancy.
Sean Kane, a partner in consumer advocate firm Strategic Safety, said Govindjee’s report does not serve the public interest.
“It doesn’t get to what risk non-recalled tires present to consumers,” Kane said. “What about the four guys in Texas who drive 300 miles at 75 miles an hour every weekend to go hunting, with a non-recalled . . . tire? Is it the same risk as the mother up in the Northeast who just drives the kids to school?”
Firestone says it has replaced more than 6 million recalled tires.
