Tired Of Each Other

But that's pretty much it for points of agreement. Ford insists that Explorers fitted with Goodyear tires have experienced far fewer tread problems than those equipped with Firestones. Firestone retorts that the same tire that shreds on an Explorer holds up just fine on a Ford Ranger. General Motors last week described the safety of the Wilderness AT tires it puts on pickups as "excellent"--although the No. 1 automaker said it was planning to switch to the Bridgestone brand for some of its vehicles this summer. (Bridgestone owns Firestone.)

One conclusion stands out amid all the examples of mutually assured destruction: while neither Ford Explorers nor Firestone tires may be unusually dangerous in their own right, the combination of the two has sometimes proved lethal. And these products share a heritage, since Firestone customized the Wilderness AT tires for the Explorer to Ford's specifications.

No company sets out to design an unsafe vehicle. But creating a car always involves making trade-offs among engineering, manufacturing, safety, sales and advertising components as well as responding to consumer and competitive pressures. It is a wildly expensive process that takes five years or so to complete.

Engineers were concerned from the get-go about the Explorer's stability during emergency handling procedures. After a test-track trial in April 1989--one year before the Explorer reached showrooms billed as a rugged and reliable family vehicle--a report noted that the SUV prototype "demonstrated a rollover response ... with a number of tire, tire-pressure [and] suspension configurations." Another report noted that the Explorer's "relatively high engine position ... prevents further significant improvement in the Stability Index [a measure of resistance to tipping] without extensive suspension, frame and sheet-metal revisions," which the company rejected.

Of course, prototypes are early versions of vehicles that are built so that designers can get the bugs out. And Ford says it got the bugs out. "In developing any product you go through variations," says Ford spokesman Jon Harmon. "Then you test them until they meet standards." He adds that the Explorer has proved to be among the safest vehicles in its class. It's not a particularly safe class, compared with cars. The Explorer had a lower rate of fatal accidents from 1991 to 1999 than 9 of 11 other SUVs. Of the most popular models, the Explorer came in two spots ahead of the Chevy Blazer but behind the Jeep Cherokee and the top-ranked Grand Cherokee. Honda's Passport was last.

In developing the Explorer, Ford's engineers were constrained from the start by previous decisions that locked the SUV onto a narrow truck frame and into a front-end suspension that was designed in the 1960s. As early as 1987, a Ford memo warned that "light-truck rollovers are 2 to 4 times the car rate" and urged Explorer developers to consider "any design action that improves vehicle stability or helps maintain the passenger safety in the vehicle." Ford maintains it did exactly this.