In the 1950s, Auto Union started to continue the work of developing plastic bodies which had been started before the war.
The driving force behind this project was chief engineer Robert Eberan-Eberhorst who wanted to add a new, small and inexpensive DKW to complete the model range. Initially designed as a three-seater (STM II), a four-seater car, the STM III on display here, was also developed at the same time. The technical uncertainties of large-scale production, for which there were no comparable reference points, meant that work on the DKW plastic car ceased in September 1956.
Technical data
| Engine | In-line 2-cylinder, two-stroke engine, air-cooled |
| Capacity | 500 cm³ |
| Power | 20 hp |
| Transmission | Front wheel drive |
| Gearbox | 4-speed |
| Wheelbase | 2,100 mm |
| Height | 1,280 mm |
| Tare weight | 390 kg |
| Top speed | approx. 100 km/h |
| Total number built | 3 units |