Ford to test tires in-house

By Richard Truett, Crain News Service©
 
DETROIT (July 10, 2001)—In the wake of its recall of 13 million Firestone Wilderness AT tires on Explorers and other vehicles, Ford Motor Co. said it no longer will take the manufacturer’s word that its tires are safe. Instead, the auto maker said its engineers will test tires to the point of failure before approving them as original equipment. ©

“We have a far greater knowledge of tires now than when we had in the mid-’90s. This knowledge could have helped us back then,” said a Ford truck spokesman. “We just didn’t do that kind of testing. That would be the tire maker’s responsibility. We had all (the) expectations that the tire maker would do that.”

Here is one example of how Ford did not test as rigorously as some competitors: In 1995, Ford redesigned the suspension of the Explorer. Ford issued new specifications for the Firestone tires and relied on Firestone for safety tests.

General Motors Corp., BMW and DaimlerChrysler A.G. said they would have tested the new tires to the point of failure.

Since late last year, Ford engineers have been conducting extensive tests on Firestone and other brands of tires by slicing them open and measuring individual parts. They also run the tires on special machines until they fail. Many of these tests will become standard.

The spokesman said the auto maker will use what it has learned in its high-tech testing and computer modeling to try to ensure that the tires it installs on its cars and trucks are safe.

From in-house testing, Ford officials concluded that the 6.5 million Firestone tires recalled by Bridgestone/Firestone Inc. last year—as well as most other Firestone tires on its trucks and sport-utilities—run hotter than competing brands and might fail more often as they age.

Ford also claims Firestone tire safety performance varies from one factory to another. In May, Ford said it lost confidence in Firestone’s tires and recalled 13 million Firestone Wilderness tires at a cost of $2.1 billion.

The National Highway Traffic Safety Administration is investigating 203 deaths and 700 injuries in Ford light trucks—most of which were outfitted with Firestone tires.

At least two other auto makers—GM and BMW—do not rely solely on a tire maker’s safety and durability test data. Both companies verify tire durability with their own series of high-stress tests.

Tire safety and performance are critical at BMW, which has built its reputation on the high-performance handling of its vehicles. BMW engineers perform several durability and safety tests, including running tires on test cars to the point of failure.

GM issues its own list of performance and safety specifications that tire manufacturers have to meet. The car maker’s engineers then subject the tires to a battery of endurance tests to ensure tires perform safely. If the tire passes, it is approved for the vehicle. Some of GM’s durability testing is done in-house and some is outsourced.

In hindsight, the shortcomings in Ford’s tire-testing procedures were underlined in 1995, when Ford redesigned the suspension in the Explorer and issued new specifications for the tire.

But Ford did not test the Explorer’s new Firestones to the point of failure—only for performance. Ford has decided that even though tire companies have the most experience carrying out intricate durability tests, it will test the limits of the tires it puts on its vehicles.

Most auto makers do not provide the warranty for tires they install on their vehicles. Replacing faulty tires is usually the responsibility of the tire manufacturer. But Ford customers have been able to get their tires replaced under warranty at many of the company’s dealers since 1999.

Although Ford didn’t carry out durability testing on the tires used on the 1995 Explorer, Ford and Firestone have said the changes to the suspension did not affect safety.

In an effort to improve the Explorer’s handling, engineers in 1995 changed the front suspension from a truck-based Twin I-beam to a more car-like short-long arm system.

Ford’s spokesman said the revamped front suspension has nothing to do with Firestone tire failures, noting that most tread separations occur on the Explorer’s rear tires.

He also cited company data from 1995 to 1997 when Ford equipped Explorers with roughly the same number of Firestone and Goodyear tires. Each brand of tire had identical performance specifications. Ford says it has documented 1,183 cases of tread separations on Firestone tires, compared with only two on Goodyear tires on 1995-97 Explorers.

“One did well, the other did miserably,” the spokesman said. “We changed the suspension for the Goodyear tires as well. It’s the Firestone tires. A thinking person cannot explain it any other way.”

Lawyers suing Ford say the Explorers most likely to flip over after a tread separation are two-door Sport models produced between 1995 and 2001. They claim that because the new suspension system weighs less, the Explorer Sport’s center of gravity is higher than it was before the suspension change.