Opinion is divided as to which is the most important part of a car. One thing is clear however: without tires, a car won’t run at all. After all, tires are the only thing connecting the vehicle with the ground, allowing the full engine power to come to bear on the road.
Tire production is a complex process and many individual components form the framework for a tire in modern production. And as tires have to satisfy the highest demands in terms of braking behavior, wet grip, rolling performance or comfort – sometimes under the most adverse of conditions – production is subjected to constant quality control.
The rubber is mixed
Different rubber mixtures with special properties are required in tire production. Like baking a cake, various ingredients are used to produce tires. For example, Goodyear Dunlop blends up to 45 different raw materials – such as rubber, silica, carbon black and sulfur – in a kneader under high pressure and immense heat. After kneading, the rubber mixture is stretched into a long strand – also known as a sheet – and then cooled and stored temporarily before being subjected to further processing.
Crucial to the tire’s carcass – and thus its rolling properties – is the textile cord, the production of which requires the highest level of precision. To ensure that the textile layer fully performs its function in the tire, stable threads are plied into a cord and then processed into a fabric that is coated with a thin layer of rubber. The sheet of fabric is cut into certain widths and angles, later forming the carcass of the tire.
Carcass of textile and steel
Another element of the tire carcass is the steel belt fabric. Its manufacture is similar to the production process for the textile fabric, except that steel wires are used instead of textile threads. The rubberized steel cord fabric is cut in the necessary angle on the steel cord cutting machine and assembled into a continuous strip.
The last component to be produced is the tire’s tread – the part that must maintain its grip on the road and transfer all forces created by the vehicle. In an extrusion process, a compound is pressed into shape under pressure and high temperature and then clearly labeled with a color mark so that the various tire models can be distinguished from one another in final production.
Tire carcass and vulcanization
Once the “semi-finished” products have been pre-produced for tire production, the actual tire assembly can begin. All individual parts are put together into a single product in a tire assembly machine. This as yet unvulcanized tire is referred to as a tire blank.
In the subsequent production phase, the plastic-like rubber compounds are transformed into elastic rubber through the vulcanization process and the individual components vulcanize with one another. To this end, the tire blank is “baked” in a heating press under a certain pressure, for a certain time period and at a certain temperature. At the same time, the blank is given its profile and sidewall lettering. Thus the basic production of a tire is complete.