EVOLUTION OF TYRES

The tyre industry had its beginnings in the bicycle industry. Solid Rubber tyres



were initially used for bicycle tyres. In 1845, R W Thomson invented and patented the


Pneumatic tyre or the “elastic bearing”. The design used a number of thin inflated tubes


inside a leather cover. But it was not until the invention of Rubber Pneumatic tyre by


John Boyd Dunlop in 1888 that pneumatic tyres started replacing the Solid tyres. In


1890s the tyre industry boomed with the boom in the demand for bicycles. But the new


tyre had a drawback. The inner tube was difficult to get at because the tyre was stuck to


the wheel. One of the first innovations in tyre industry was the solution to this problem


when in 1890; Jack Welsh patented the design of the wheel rim with extensible outer


cover lip.By 1900, tyres had more or less round cross sections with bodies of cotton



reinforced fabric. Treads were introduced around 1910 and layers of reinforcing cord


around 1920. Synthetic rubber was beginning to be used in the 1930s.






As demand for bicycles waned off, the automobile industry started driving the


tyre industry. And even today, tyre industry is primarily driven by the automobile


segment. As automobiles become faster and heavier the need for improved design


became necessary. The new developments were the introduction of patterned treads,


balloon tyres, radials and so on. In the 1920s and 1970s tyres became wider and flatter


and had improved life span. But two of the most important technological turning points in


the tyre industry were the introduction of radial technology by Michelin in 1948 and the


doing away of inner tube on car tyres in 1972.






The technological history behind the tyre that we see today is interesting,


especially with the two main technologies namely, bias-ply and radial ply existing side by


side. Initially only the bias-ply technology was there but during the 1960-70s, the radial


ply technology found its way in the market. There are major differences between the bias


tyres and radial tyres.
 
Technically, these two variants differ in the way the ply cords (which means the



layers of fabric that makeup the body of the tyre) are layered in the body of the tyre. In


bias tyres the ply cords are at an angle to the direction of rotation or diagonally across the
 
tyre from bead to bead. These ply layers alternate in direction to reinforce each other. On


the other hand in radial tyres the ply cords are perpendicular to the direction of rotation or


run radially across the tyre from bead to bead.

Performance wise, radial tyres surpass bias tyres when it comes to smooth rides



on bumpy roads and tyre grip on wet road conditions. Other plus points for radial tyres


are better braking and cornering power, better gas mileage and a higher life expectancy.


Seeing the inrush of radial tyres, the bias tyre manufacturers introduced the belted bias-


ply tyre in 1967. It had the same ride characteristics as the bias tyre but its life expectancy


was increased