CarBrandLogos archive · DKW · 1939

DKWRT 125

The most copied motorcycle design in history, taken as war reparations.

The story

A defining chapter in DKW history.

Explore the ideas, engineering and context that shaped the DKW RT 125, then continue into its specifications and place in the marque's lineage.

Origins

The RT 125 was a modest thing: a 125 cc single-cylinder two-stroke with a three-speed gearbox, designed at DKW's Zwickau works and introduced in 1939. It was light, cheap, simple to build and simple to fix, and DKW's engineers had solved the loop-scavenging problem well enough that it ran cleanly and reliably where earlier small two-strokes had not.

RT125 · No machine-readable author provided. Idms60~commonswiki assumed (based on copyright claims). · Public domain

Design and engineering

The war changed its status entirely. DKW built thousands for military use, and when Germany was defeated the design was handed out as reparations — drawings, tooling and, in some cases, whole machine shops. What followed has no real parallel in industrial history.

PL Sokół 125 motorcycle · Hubert Śmietanka vel Hiuppo · CC BY-SA 2.5

In production

In Britain, BSA built it as the Bantam, reversing the drawings for a right-hand gear change, and sold enormous numbers to commuters, learners and the GPO. In America, Harley-Davidson built it as the Model 125, later the Hummer. In the Soviet Union it became the Moskva M1A and then the Minsk. In Poland it became the WSK; in Japan, Yamaha's first motorcycle, the YA-1, was closely based on it, and the company that grew from that machine needs no introduction. In East Germany, the original works continued as IFA and then MZ, developing the design further.

PL SHL M04 motorcycle · Hubert Śmietanka vel Hiuppo · CC BY-SA 2.5

Legacy

The reason it travelled so well is that it was designed to be manufactured by people without much equipment. The engine has few moving parts, the frame is simple, and the whole machine could be assembled in workshops that had spent the previous decade making something else entirely. Countries rebuilding their industries did not need to design a motorcycle; they needed to build one, quickly, and here was a proven design with the drawings already in hand.

Chapter 5

The RT 125 mattered because of what it enabled rather than what it was. For a generation across four continents, the first powered vehicle a young person owned was some version of this bike, and several of the world's largest motorcycle manufacturers were founded or rebuilt on copies of it. West German DKW carried on making its own developments of the design into the 1950s, by which point everyone else had too.

Technical specification