A tire is a complex combination of components made from numerous ingredients. But how do we get from the rubber tree to the road? Tire production is a multi-step process. Let’s follow a Continental tire through all five essential stages of tire manufacturing:
Various branches of industry supply the tire manufacturing industry with raw materials, which are used to create the necessary compounds.
Steel. The steel industry supplies high-strength steel. This serves as the starting material for the manufacture of steel belts (steel cord) and of bead cores (steel wire).
Chemicals. The chemical industry is a major tire ingredient supplier. In particular, synthetic rubber and materials used to reduce wear, increase grip, and extend the life of a tire.
Natural rubber. Rubber is extracted from special trees grown in large plantations. The milky fluid (latex) that flows out coagulates when acid is added to it. It is then cleaned with water and pressed into solid bales for easier transportation and storage.
Bales of natural and synthetic rubber are sectioned, cut into portions, weighed, and mixed with other ingredients according to precise recipes. Up to twelve different rubber compounds are used in modern passenger car tires.
Textiles. The textile industry supplies base materials (rayon, nylon, polyester, and aramid fibers) for the manufacture of cords that serve as reinforcement in tires.
Steel cord. Pre-treated steel cord supplied on wire spools is fed into a calendar, where it is embedded in one or more layers of rubber. The result is a continuous sheet of cord and rubber. This is cut at a defined angle to the correct length according to tire size and rolled up for further processing.
Tread. Kneadable rubber material that has been blended in a mixer is now ready to be made into the tread. A screw-type extruder shapes the rubber into an endless strip of tread. After extrusion, the weight per meter is checked and the tread cooled by immersion. The tread strip is cut to length for the tire size. Another unit weight control is then carried out.
Textile cord. A multitude of textile threads are fed into the calendar by a large roller device and embedded in a thin layer of rubber. This endless sheet is then cut to the desired width at a 90° angle to the direction of travel and rewound for further processing.
Steel bead. The core of the bead is made up of many ring-shaped steel wires. Each of them has its own rubber coating. This loop is then fitted with a rubber apex.
Sidewall. Sidewall sections cut to suit the particular tire size are turned out with the extruder.
Inner liner. A calendar forms the airtight inner liner into a wide, thin layer.
Now, the tire building can begin. The various semi-finished products come together on the tire building machine and are assembled into what is known as a “green tire.” This is done in two stages: the casing, and the tread/belt assembly. This “green tire” is then sprayed with a special fluid to prepare it for vulcanization.
Now we’re in the curing press. Here, the tire receives its final shape after being vulcanized for a certain length of time at a certain pressure and temperature. During this process, raw rubber becomes flexible, elastic rubber. Curing press molds are engraved with the tread pattern and sidewall markings.
Each individual stage of production – from the inspection of raw materials to delivery of finished tires – is subject to ongoing quality control.
A multi-layered process ensures Continental tires are thoroughly checked for quality. Finished Continental tires go through:
Once tires have passed all checks and inspections, they are sent to the distribution warehouse for shipment.