
Soon after DKW began manufacturing their own bicycles with mountings for their popular bicycle auxiliary motor, the DKW Hilfsmotor, experiments began to develop a proper motorcycle. The first vehicles were motor scooters - Sesselrads in German - such as the Golem and Lomos. These were not very successful and production soon stopped and the leftover parts were used to develop motorized delivery tricycles, which were popular light commercials during this period. https://dkwautounionproject.blogspot.com/2023/11/dkw-dgw-delivery-triporter.html
In 1922, designer Hermann Weber set about modifying the DKW bicycle with an improved and strengthened frame capable of mounting the DKW Hilfsmotor within the 'triangle' of the bicycle frame. The motor was bolted to the lower frame and a long petrol tank was fitted over the top frame. To improve the engine's efficiency it was given a cooling shroud which directed a modicum of fresh air over the cylinder fins. Drive was by belt to the rear wheel as with the Hilfsmotor, except now the belt ran between the riders legs. A rudimentary silencer directed the exhaust downwards but exhaust gases were not piped away from the rider as in modern motorcycles. The engine was single speed without a clutch, which would be introduced in 1925. The bike still had pedals and the rider would start the motor by pedaling or via a hand-lever on the side of the engine (carried over from DKW's stationary motor range).
This was an extremely primitive machine but thanks to its successful performance in the 1922 Reichfahrt race followed by endurance and speed trials on the AVUS track later that same year. To capitalize on these successes, the model was subsequently renamed the Reichfahrtmodel. The engine underwent rapid improvement, being uplifted from its original 118ccs to 148ccs.


Year-on-year DKW's motorcycles underwent rapid improvement. In 1925 a clutch was introduced, carried over from the Lomos scooter and a two-speed gearbox. The engine was also set upright at the bottom of the bicycle frame, instead of leaning forward. The pedals were dropped entirely and footplates were fitted for the rider. Front suspension was improved with damping springs. Drive was still via belt to the back wheel. The new bike, the 'Sportsmodel mit Getribe' (sporting model with clutch) was still quite archaic compared to contemporaries, but it was cost effective and performed well.

The ZM model (meaning Zschopaur Model) of 1926 was an improvement over the Leichtmodel. The engine and gearbox was redesigned into a more compact unit. A kickstarter was now fitted to the engine, replacing the hand lever. Five engine variants were available during the model's short, two-year, production run - 128cc, 170cc, 178cc, 181cc and 206cc. The multiplicity of capacities were developed to exploit the complex German road-tax rates.

At the same time as the ZM model, DKW introduced the experimental SM (Stahlmodel). The SM (steel model) used the same engines / clutch / gearbox as the ZM but the body was constructed of pressed steel plates rather than rolled steel tube. The central beam of the body housed the petrol tank. Drive was still via belt to the rear wheel. The experiment with pressed steel bodywork would not prove successful however as the welded seams exhibited a tendency to crack over time and production was stopped after approximately 1000 units had been built.

From 1926 DKW motorcycles began to advance rapidly. New moving production-line methods at Zschopau increased production volume substantially. Additional features were added to the range, such as electric headlights, luggage carriers, panniers, performance carburetor options, etc. The bikes and their engines improved in quality and performance - although this was still pre-reverse scavenging and nose pistons were still the standard. It would be in 1929 that the Schnerle patent for reverse scavenging would be secured and DKW motorcycles made a quantum leap forward.
From the Boy's Wish to the Little Wonder: https://dkwautounionproject.blogspot.com/2020/07/from-boys-wish-to-little-wonder.html
Das Kline Wunder: https://dkwautounionproject.blogspot.com/2017/06/das-kleine-wonder-story-of-remarkable.html
DKW Super Sport ersatzteilelist: https://dkwautounionproject.blogspot.com/2025/07/1926-dkw-super-sport-ersatzteilelist.html
DKW Hilfsmotor: https://dkwautounionproject.blogspot.com/2025/07/1920-dkw-hilfsmotor.html
No comments:
Post a Comment