Protecting Safety of Ford Customers
I've been an admirer of Holman Jenkins's commentary for many years, and thus am especially disappointed that his Business World column yesterday misses the most important issue raised by our action to replace the remaining Firestone Wilderness AT tires. We saw in claims data, recently supplied to us by Firestone, early warning signs that some of the tires would over time not adequately protect our customers' safety. We acted on those signs without prodding from NHTSA, and at considerable cost. Firestone is unhappy with our action, but our customers' safety is paramount.
Mr. Jenkins's statements around our Firestone Wilderness AT tire replacement program rest on seriously flawed assumptions. In particular, he challenges the 26 psi recommendation for the recalled Firestone tires and asserts that this, combined with their "C" temperature label, explains their failures on the road. This is not consistent with a scientific examination of the facts.
Ford did not recommend 26 psi to lower the Explorer's center of gravity, since tire pressure has nothing to do with a vehicle's center of gravity. (A 4 psi decrease lowers the center of gravity by 90 thousandths of an inch.) The 26-psi recommendation, tested and then warranted by Firestone for more than 10 years, was calculated to optimize the Explorer's comfort, performance and handling. The same inflation pressure has been adopted for many comparable SUVs.
The 26-psi specification was obviously sufficient in the case of the 2.9 million Goodyear tires used on more than 500,000 Explorers -- then and now. Those Goodyear tires have performed on Explorer at an industry-leading level of safety, traveling more than 25 billion miles.
Note also that the failure rates on the Firestone 15-inch tires varied dramatically from factory to factory, a statistically validated finding that triggered last year's Firestone recall. Since the 26-psi recommendation is the same regardless of where the tires were produced, it plainly does not explain the tires' varying performance on the road.
Moreover, our Firestone replacement program also includes 16-inch Wilderness AT tires. Those tires, despite a higher recommended pressure of 30 psi, appear to have failure rates at least equal to the failure rates of some of the 15-inch Wilderness tires and considerably higher than competitive tires in the field.
Tires certified with a "C" temperature label have passed a stringent government standard, and are therefore determined to be fully acceptable. In fact, there are millions of "C" tires on GM, Toyota and Nissan SUVs, and these tires appear to have performed well despite their presence on vehicles of larger weight and load carrying capacity than the Explorer.
Perhaps more importantly, one must understand the tests behind the ratings. The "temperature" rating is run only on a test drum, with loads greater than the tires experience in the real world. In fact, the 85-mph threshold a tire must pass on the test drum to be certified actually translates to speeds significantly higher in on-road usage by our customers.
There is a separate test that certifies tires for a speed rating. This test is run at higher speeds and full vehicle loads. All Wilderness AT tires are speed rated "S" and are certified to 112 mph, substantially higher than the top speed of an Explorer.
Ford is not in the business of designing or manufacturing tires. We instead set basic performance criteria for the tires supplied by companies such as Firestone or Goodyear. The same performance criteria were given to both Firestone and Goodyear in the case of the Explorer tires. The disparity in the real-world performance of these tires -- failure rates 600 times greater on the Firestone tires versus an equal number of Goodyear tires on the same vehicle -- is the reason we are acting in a preventive manner to replace all Wilderness AT tires on our customers' vehicles. Ford is in the business of satisfying and protecting the safety of our customers.
John M. Rintamaki
(Last August, Mr. Rintamaki was given company-wide responsibility for leading the tire team at Ford by President and CEO Jacques Nasser.)