In 1911, Karl Kassborer planned to open a bus route Wieblingen — Ulm-Wieblengen. For this purpose, a separate transport company was opened and a bus was built on the chassis of a Saurer truck by the Kässbohrer company. The trucks of this Swiss company were of excellent quality and were sold in many European countries.
The first Kässbohrer bus had a 30 hp four-cylinder engine. The body of the bus did not indulge in the comfort of passengers. But the device turned out to be durable and worked for a long time on the Wiblingen-Ulm-Wiblengen line.
As it is not surprising, but at first buses were not the main activity of Kässbohrer. Preference was given to trailers and semi-trailers for trucks. And today Kässbohrer trailers are on the market, but they are much less known than Setra buses.