This is the first in a series of articles on automobile tires by John Thomson. 
The next article will look at how tires are tested and rated.

The first rubber tires appeared in the mid-1800s. They were solid or cushion tires in which the rubber itself carried the load, absorbed shocks, and resisted cutting and abrasions. The pneumatic or air-filled tire, which carried the load and absorbed shocks by the compressed air in the tire casing, was patented as early as 1845. Solid rubber tires were preferred over pneumatic tires because of their durability, so pneumatic tires fell into disuse. The popularity of bicycles in the late 1800s revived the idea of the pneumatic tire, and in 1888 a Belfast veterinary surgeon named John Boyd Dunlop obtained a patent for a pneumatic bicycle tire.

The first use of pneumatic tires for automobiles was pioneered by the Michelin brothers, André and Édouard. They equipped a car with pneumatic tires and drove it in the 1895 Paris-Bordeaux road race. Though André and Édouard didn’t win the race, they generated popular interest in pneumatic tires, and Michelin & Cie became a leading producer of tires in Europe. At the same time, solid rubber tires disappeared from the highways, mostly because of legislation that discouraged their use because they were hard on the roads.

In 1898 Goodyear Tire and Rubber Company—named after George Goodyear, the discoverer of vulcanized rubber—was formed in America by Frank Seiberling. Then Firestone Tire & Rubber Company was started by Harvey Firestone in 1900. Other tire makers followed.

For the next fifty years automobile tires were made up of an inner tube that contained compressed air and an outer casing that protected the inner tube and provided traction. The rubber that made up the casing was reinforced by layers or "plys" of rubberized fabric cords embedded in the rubber. The tires made during this period were known as bias-ply tires because the plys ran across the tire in alternating diagonal layers at about a 55 degree angle to the wheel rim. Bias-ply tires continue to be made and are sold as authentic equipment for antique and collector cars that were made during this period.

Michelin first introduced steel-belted radial tires in Europe in 1948. Radial tires are so named because the ply cords radiate at a 90 degree angle from the wheel rim, and the casing is strengthened by a belt of steel fabric that runs around the circumference of the tire. In radial tires the ply cords are made of nylon, rayon, or polyester. The advantages of radial tires include longer tread life, better steering characteristics, and less rolling resistance, which increases gas mileage. On the other hand, radials have a harder riding quality, and since they are technologically more complex than bias-ply tires, they are about 45 percent more expensive to make. Because of their construction, radial tires require a different suspension system from that used by cars designed for bias-ply tires. It is generally recommended that radial tires not be used on cars designed for bias-ply tires.

Over the next 20 years radial tires became standard on new cars outside of America. Michelin in France, Bridgestone in Japan, Pirelli in Italy, and Continental in Germany became powerful radial tire manufacturers. Automobile tires everywhere became tubeless as tire technology improved, but what happened to radial tires in America? Therein lies a tale.

Both the American automobile manufacturers and the tire companies fought the radial tire. Detroit, home of the American automobile, was afraid of how much it would cost to redesign automobile suspensions to accept radial tires. The tire industry was afraid of how much it would cost to retool the entire American tire industry to make the more costly radial tires. Not happy with the threat of having to make tremendous investments, most American automobile makers and tire manufacturers wrote off the radial tire as "a freak product that isn’t going anywhere."

With the notable exception of B.F. Goodrich, the American tire companies decided that the American public wasn’t ready to pay a lot more for the harder ride that radials produced, and they stuck to making bias ply tires. Goodrich bucked this trend by investing heavily in radial tire technology, only to have their tire—the Silvertown Radial 900, introduced in 1965—snubbed by the American automobile industry. Eventually Goodrich sold its tire operations and got out of the tire business.

In 1967, Goodyear, the world’s largest tire company, introduced their response to the radial, a bias-belt product called the Custom Superwide Polyglas. The bias-belted tire simply added a fiberglas belt to the bias-ply tire. The bias-belted tire would last 30,000 miles compared to 40,000 for radial and 23,000 for bias-ply tires. It could be used on cars designed for bias-ply tires. Best of all, it could be made on existing bias-ply tire-making machines, which made its cost not much more than a bias-ply tire.

Fueled by a Goodyear advertising blitz, bias-belted tire sales rose from 2 percent of the original-equipment market in 1968 to 87 percent by the early 1970s. In advertisements touting their bias-belted tires, Goodyear ridiculed radials for their hard ride and their high cost. The American tire and automobile industry was confident that the bias-belted tire would keep the radial tire wolf from the door for a while and expected to have plenty of time to develop their own radial tire expertise at their own pace.

Then came 1973 and the gasoline crisis. Gas went from 30 cents to a dollar a gallon. Americans demanded more economical cars. That year, imported cars represented 15% of American auto sales, but by the early 1980s imports were 28 percent. Of course, each foreign car came equipped with radial tires. Americans clamored for radial tires when they found that they improved gas mileage. Companies like Michelin and Bridgestone were only too happy to supply the American market.

Alas, in the mid-seventies Firestone Tire decided to get into radials on the cheap, fabricating radial tires on machines made for building bias tires. The tires came apart in a spectacular manner. Firestone recalled close to 9 million of its Firestone 500 steel-belted radial tires. From 1977 to 1980, Firestone’s tire business dropped 25 percent, resulting in the layoff of 25,000 workers. The company went from a $110 million profit to $106 million loss, and its stock dropped from $15 down to $10 a share. Firestone was rescued when Bridgestone Tire bought them in 1988.

Goodyear finally produced a radial tire in 1977 by investing billions of dollars in radial technology. Other American tire companies either merged or were bought out. All American new cars came with radial tires by 1983.

Currently Goodyear holds about 20 percent of the global market share in radial tires, both original equipment and replacement; Michelin, 19 percent; Bridgestone, 17 percent; Continental, 9 percent; Pirelli, 5 percent; and the others, 30 percent.