Getting It Wrong
Customers who bought Firestone’s “500” steel-belted radial tires began having problems with tread separation shortly after the tires were introduced in the early 1970s. But when they brought the tires in, the company couldn’t understand why its new flagship product was failing. Executives stonewalled. They blamed consumers for poor maintenance or bad driving habits, and the company resisted outside inquiries. Finally, in 1978, the U.S. government pressured Firestone into a “voluntary” recall of what eventually totaled 8.7 million tires, citing figures showing 41 deaths and 65 serious injuries attributable to the tread separations. The recall nearly crushed the company and may have helped enable Japan’s Bridgestone company to purchase Firestone in 1988.
But the recall couldn’t crush radialization. Even with Firestone’s problems, the advantages of the new technology were obvious to industry and consumers alike. “It was never going to die. It had too much to offer,” remembers Bill VandeWater, who was an engineer in radial sales for Firestone. Still, “we did it wrong, and it was very difficult to keep morale up during those days. It just seemed like everything we did was wrong. We fought the whole system, we were blaming it on consumers, we were doing all the wrong things.”
When Firestone engineers finally dug into their tires to find out what was happening, rusting turned out to be the answer. Every tire receives cuts, many of them deep enough to reach the belting inside. Firestone’s steel belting in the 500 was constructed of bundles woven from five cords. When a cut penetrated the tread, the cord design allowed salt-carrying water to wick along the cording, often all the way across the tread. The steel would rust, and a separation point would be created within the tire. This was a problem that developed over time—generally a year or more—regardless of how many miles the tire had been driven. “We didn’t understand the mechanism,” VandeWater concedes. “As soon as we realized that, we started making tires a little bit heftier, testing them in more overloaded conditions, testing them longer.”
Firestone installed salt-bath areas in its test tracks and intentionally slashed tires to study rust and oxidation wear. The company came up with a new tire, named the 721, with a steel structure of seven cords over two and a spiral-wound cord to hold the bundle together. One of VandeWater’s jobs was to sell the Ford Motor Company on the tire; it wasn’t easy being a Firestone engineer in those post-recall days.
But the irony of the Firestone 500 failures was that they might never have happened during bias-tire days. Back then, tire life had been so low that there wasn’t enough time for the belting to deteriorate. Nonetheless, Firestone was alone in mishandling a problem that other manufacturers were also facing. “Actually, in talking to people from other companies, we found our situation was very comparable to theirs,” VandeWater says. “They were having the same problems in the field that we were. It was just that when their customer came in with a problem, they’d say, ‘Sure, we’ll fix it.’ We said, ‘No, it’s your problem.’”
In the end, the Firestone 500 still turned out to be one of the best-selling radial tires ever, and the need for new durability testing was proved beyond a doubt.
