TYRE. The tyre of a wheel is the outer circumference por tion that rolls on the ground or on a track prepared for it. Rail way vehicle wheels usually have hard steel tyres, which together with the hard steel rail give the maximum endurance and the minimum rolling resistance. The common tyre made for the exterior rim of non-motor road-vehicles serves to hold together the parts of the wheel and resists wear in -travelling. It is ordi narily made of iron or steel, and consists of a flat hoop formed so as to fit tightly over the exterior of the wheel. Its chief considerations are strength and durability. In bicycles, motor cars, and other road-vehicles in which freedom from vibration and shock is also desired, solid or pneumatic rubber tyres are employed.
The principle of the pneumatic tyre was patented by Robert William Thompson in England in 1845, in France the following year and in 1847 in the United States. Thompson's patent sub stantially covers the tyre as it is known to-day. It showed a non stretchable outer cover and an inner tube of rubber to hold air. An early set of tyres made on this basis covered 1,200 miles when placed on an English brougham.
Almost half a century later, when the bicycle became popular, pneumatic tyres were revived by John Boyd Dunlop of Belfast, Ireland. He obtained certain patents in 1888 and 1889 on Eng lish bicycle tyres. A year after Dunlop's patents were issued,
Charles K. Welch patented a tyre shoe of fabric having wire edges and a rim to clinch the shoe and hold it to the felloe of the wheel. In 1892 a United States patent for a similar tyre was granted to A. T. Brown and G. F. Stillman. This was pur chased by the Dunlop Company and these clincher tyres were manufactured in its American factory and, under licence, by the Diamond Rubber Company. In 189o, the first clincher tyre held in position by inwardly-curved flanges of the wheel rim was patented by William Erskine Bartlett, an American residing in England, and in 1892 another by Thomas B. Jeffery in the United States. Both of these were pronounced valid by the courts. The thread or cord tyre was patented by John Fullerton Palmer in England and in the United States in 1893. Pneumatic tyres were first applied to motor-vehicles by a firm of French rubber manufacturers, Michelin and Company. After some improve ments were made, rubber tyres were adopted by Panhard and Levassor and other French automobile manufacturers about 1895. The first tyres used in America on commercial motor-vehicles were made by the B. F. Goodrich Company in 1896 for Winton cars manufactured in Cleveland. These were single tube tyres.