The first tires initially had form of a large cylindrical tube. In 1904 they already have tread and the addition of a carbon black makes them more solid and durable and gives them the typical black color. In the 20s the tire already has a supporting body, made of cotton fabric and in the middle of the same decade the balloon tire is invented. The pressure of balloon tire is reduced from 5 to 3 bars, which significantly improves ride comfort. In the 40s this type of tire is followed by the superballoon tire that contains more air and provides more comfort.
Until the 70s of XX century all tires are still diagonal. They consist of a number of layers, in which fabric the constructing fibers are combined with rubber and the whole payers “wrap” bearing metal ring. The number of layers is determined by the load capacity of the tire. The individual layers are crossed diagonally (here comes their name) at a certain angle from which depend the stability and the comfort. The higher angle for example provides more comfortable ride and the smaller angle ensures stability in sports cars. And nowadays some the OTR tires producers prefer diagonal structure, which because of the strong crossed payers remain more stable of loading. As we will see later, due to the friction this type of tires are not suitable for high speeds, at high-speed turns and curves they strongly deform and have no enough contact surface.
In the early 50s Michelin the radial tire was invented by Michelin. The mass replacement of the diagonal with radial tires began in 70s. The usage of diagonal tires decrease progressively and soon after that the low profile tires appeared – initially with 70% profile, and after that with 60% and 50% profile. Nowadays you can find sport tires with height index lower than 25%.
At the dawn of the evolution the supporting structure of the tires was made of rubber-coated braided fabric. However, it has a serious problem – between the crossed fabrics there was a strong friction force, as a result of it the tire was heating and its durability was reduced. In 1923 Continental implemented fabric in which the fibers are positioned in one direction.
Modern tire is a complex mixture of components, depending on itsdesign and price. The average radial car tire with metal belt can be defined as containing:………………………
For the truck tyres the relative share of synthetic rubber is considerably smaller, but the percentage of carbon black, steel and supplements is increased.
Various types of rubber are mixed according to the respective requirement – some of them are extremely resistant to tension, retain their properties over time, have a high resistance of the molecular structure – an example for this is the natural rubber and styrene butadiene. Natural rubber is also resistant to abrasion wear, while some synthetic products such as chlorobutyl resist on high temperatures.
Thanks to computers and relevant software products tire manufacturers can dose natural and synthetic components of the compound depending on the purpose and to add relevant stabilizing agents in different proportions.
A race tire, for example for F1, has different structure compared to the conventional ones because of its specific usage – it has carbon fibers in its supporting construction, made of compound which just “stick” to the road and due to that maintain high temperature. The cost of all this is its short life.