A conventional car tire casing contains about 400 g of polyester yarn.
Polyester, in the form of tire cord, is an essential component of the tire carcass. The tire cord influences the tire's durability, load-bearing capacity and comfort. It is the backbone of the tire, carries the load and absorbs shocks. In this respect, the material must retain its shape even at very high temperatures, which is why thermal stability is crucial.
Tire cord consists of so-called HMLS (high-modulus low-shrinkage) yarns. These preliminary polyester products are extremely tear-resistant, while nevertheless remaining highly elastic and stable in terms of their dimensions and temperature. This is important to ensure the tire also retains its shape when it is insufficiently inflated and heats up more due to the corresponding increased friction on road surfaces. The cord, a fabric made from twisted HMLS yarns, is united with the tire rubber at approximately 200 degrees Celsius. It lies between several layers of rubber and stabilizes the entire car tire on roads.