Hans Ledwinka, who left the company in 1902, was hired back in 1905.

Immediately, he started working on a new car with a modern and progressive design.

The rear axle was driven by a drive shaft in lieu of chains.

[1] The S4 and S6 with four- and six-cylinder engines, respectively, were able to reach maximum speeds of 80 km/h and 100 km/h (50/62 mph).

The later, six-cylinder S6 40/50 version was an S4 with two cylinders added; it produced 50 PS (36.8 kW) and was introduced in 1910.