WASHINGTON (July 22, 2005) — Some of the statements made by a top Ford Motor Co. polymer scientist in a 2004 court deposition seem to go against the reasoning that led the auto maker to recommend its vehicle owners replace their tires after six years regardless of condition, according to tire industry spokespersons.
“We find this to be very contradictory with Ford's actions,” said Becky MacDicken, government affairs director for the Tire Industry Association (TIA), regarding the deposition given Dec. 17 by John M. Baldwin, the Ford polymer science technical specialist who leads the car maker's research in tire aging.
Based on the results of Mr. Baldwin's research, Ford said in May, the company decided to advise its customers to replace their tires after six years of normal service, regardless of their condition.
“Based on these statements, we would submit that Ford doesn't have data showing a direct correlation between tire age and tire performance,” added a spokesman for the Rubber Manufacturers Association (RMA). Earlier, the association said that neither Ford nor DaimlerChrysler A.G.—which said it will add the six-year tire replacement recommendation to its owners' manuals starting with the 2006 model year—had ever shared their tire aging data with either the association or its tire manufacturing members.
A Ford spokesman declined comment to Tire Business on the record regarding the Baldwin deposition.
Mr. Baldwin was deposed in a case before the Texas 117th Judicial District Court, according to a copy of the document obtained by Tire Business. At the beginning of the deposition, Mr. Baldwin said it became obvious from studying some of the Firestone ATX, ATX II and Wilderness AT tires recalled by Bridgestone/Firestone in 2000 that the properties of the rubber were changing “dramatically” over time.
“If you put a new tire vs. a 4-year-old tire on a road wheel and let it go…to failure, my belief is that an older tire would fail faster on any particular test,” he said.
In other places during the deposition, however, Mr. Baldwin seemed to qualify this statement.
When asked whether older tires are less resistant than new ones to belt edge separations, he answered: “I'm not comfortable making that assessment yet, to be honest with you.”
Asked whether he agreed that oxidative aging occurs in all tires over time, he replied: “Disagree. It depends on a lot of other factors.”
Mr. Baldwin also disagreed with the assertion that oxidative aging of inflated tires has been well known for a long time, saying, “There's not a lot of literature on it.”
Discussing the results of oven aging tests on tires, Mr. Baldwin said, “Oven aging tires either unmounted or mounted with air for the two weeks has very little effect on the chemical and physical properties of the belt package rubber. Only when mounted with the 50/50 oxygen-nitrogen…do properties significantly change.”
Mr. Baldwin said he planned to compare new and oxidatively aged tires to see if cracks began and grew more rapidly in the aged tires.
He also said he hoped to complete this work in six months or more, meaning it could be done sometime this summer.
At the end of the deposition, Mr. Baldwin said Ford was not collaborating with any tire companies in its tire aging research. He also said he was not aware at that time of any backlash from the tire industry regarding Ford's research.
In March 2004, Mr. Baldwin told an audience at the Clemson Tire Industry Conference in Hilton Head, S.C., that aging is a crucial element in tire degradation, and that his research of the recalled Firestone tires demonstrated this.
“When you look at two vs. four years of service, peel strength had dropped 50 to 75 percent in the field,” he said. “Obviously, the rubber's changing.”
The tire industry has long insisted there are too many variables in tire aging to postulate any sort of expiration date for them. In early 2004, it beat back an effort by Sen. Mike DeWine, R-Ohio, to include a tire expiration date provision in a larger motor safety bill.
In June of this year, in reaction to Ford's and DaimlerChrysler's tire-age recommendations, the RMA wrote the National Highway Traffic Safety Administration (NHTSA), asking it to issue a consumer advisory outlining the factors that affect a tire's service life.
Meanwhile, the RMA and TIA are waiting on the results of the American Society for Testing and Materials' efforts to devise a testing protocol for tire aging. The ASTM committee handling this effort, which includes a number of tire industry scientists and officials, is working in conjunction with NHTSA in the agency's efforts to devise a tire aging test for federal tire safety standards.
“There are so many variables involved that we honestly don't know whether they'll ever come up with an accurate test,” Ms. MacDicken said.
“This underlines our feelings that Ford was at the very least premature in its recommendations to its customers.”