In the beginning there were wheels but no tires.
Horseless carriages, one of the technological marvels of the late 19th century, traveled on solid wheels made of wood or metal.Then innovators, including the Frenchman Andre Michelin, then experimented by fitting wheels with rubber tubes. Michelin favored filling them with compressed air; some of his comtemporaries peferred to fill the tubes with sand or hay. As every modern driver knows, compressed air was best as absorbing shocks from the road.
Tires gained treads - after the invention of equipment that could cut grooves in hard rubber - and a stiff outer carcass reinforced with cords made of cotton, fiberglass or steel.
Now, some tires are literally coming apart.
Customers say that the treads have peeled off Firestone's ATX and Wilderness AT tires, models that were fitted as original equipment on the Ford Explorer sports utility vehicle and on light trucks.
Safety officials have so far linked the tire to at least 88 deaths and 250 injuries - figures that may be revised upward after the National Highway Traffic Safety Administration finishes a review of crash data, perhaps as early as this week.
Firestone has recalled 6.5 million tires and promises to replace them at the company's expense. But Firestone has said that stability problems of the Explorer may be part of the problem: The company says that the vehicle seems more difficult to control than most after a tire failure, and thus more likely to overtrun and injure the occupants.
Firestone has acknowledged the existence of manufacturing problems at the company's Decatur, Ill., factory, where many of the failed tires were produced. Tire company officials have also cited Ford's recommendation that the tires be inflated to a relatively low 26 to 30 pounds.