The history of wheels 3

Motor car tyres at that time, were pumped up to a pressure of 5 bar. This is not the only reason why they were a menace for the motorists. They had to be checked before each trip, which they often enough didn't survive. In the course of a race, up to 50 tyre-changes were quite normal. For this reason, it was considered a blessing, when the removable wheel-rim was finally introduced in 1905.

Tyre-codes and the respective standardisation have been around since 1903 (Friedrich Veith). Continental first supplied tyres with a tread in 1904 (see above pictures). Minor tyre damages could possibility be repaired on the spot, those with more serious damages had to be sent in for an uncertain duration. New tyres were only bought in exceptional cases. In spite of the amount that was paid for other repairs and the short service intervals, the tyres were considered to be highest expense. Sometimes more was spent on tyres than was for fuel.

To increase the mileage performance fivefold, the low-pressure tyres were introduced in 1920. Almost just as important, was the mixing in of a product, which is simply described as 'soot'. This is not simply that which is removed from the kiln after the burning, but an industrially made substance with a carbon content of at least 80%.

In the beginning, solid rubber tyres (see pictures) were also superior as far as load-carrying was concerned, thus, they were still used on trucks for a long time. Even into the second half of the last century, they could still be found on carny-trailers and circus wagons. The pneumatic tyres were not suitable for trucks, due to the heavy loads of up to five tons that they were transporting. Unfortunately, also the solid rubber tyres were not free from wear and tear, particularly when they became heated.