The other German bike maker
The appearance of a replica of a TT-winning DKW at the recent Classic TT came about thanks to the Audi Tradition team, which promotes the history of Audi’s former parent Auto Union, of which DKW was also a part. The bike that turned up on the Isle of Man was a replica of the 250 ULD ‘Ladepumpe’, a kind of supercharged two-stroke that won the 1938 Lightweight TT.
Before WWII DKW was the world’s largest motorcycle manufacturer, with an R&D department that spewed out ingenious engine designs with a frequency that must have bewildered the more slothful British industry. The company’s racetrack successes of the 1930s were based on its perfection of the split-single format, supercharged by a third piston (the ladepumpe).
Inspired DKW engineer Ing Zoller arranged two tandem cylinder bores in a single casting with a common combustion chamber, rotary-valve intake, articulated connecting rods and a third piston in a separate cylinder that supercharged the gases through the main crankcase (this was a two-stroke, remember). At the same time the rear piston had a permanent lead over the front piston to drastically improve cylinder filling. The result was a huge hike in horsepower and fuel consumption, as well as paralysing noise.
Legend has it that when Ewald Kluge roared down Bray Hill during his winning ride the DKW’s howl could be heard on the Lancashire coast. In spite of shocking fuel consumption that required an extra pitstop despite the bike’s enormous five-gallon tank, Kluge beat Ginger Wood’s Excelsior by more than 11 minutes.
A member of Hitler’s Nationalsozialistische Kraftfahrkorps (National Socialist Motorised Transport Corps), Kluge took the podium wearing a swastika on his leathers. Unlike compatriot Georg Meier, winner of the 1939 Senior TT for BMW, he didn’t perform a Nazi salute during prize giving. Nevertheless, Kluge was denounced as a Nazi at the end of the war and spent five years in a Russian prison camp. On release he rode DKWs once again, until his career was cut short by injury.
The war changed everything for DKW. The factory found itself behind the Iron Curtain, so the company started again in Ingolstadt, West Germany, where Audi still resides. And because supercharging had been banned when racing resumed, DKW’s surviving engineers couldn’t continue with the split single. Yet their ability to create brilliant engines remained undimmed.
In 1951 Germany was readmitted to international racing after a six-year ban and it didn’t take long for DKW to prove that they didn’t need supercharging to win races. Their most brilliant design – a three-cylinder 350 – soon became the fastest 350 in Grand Prix racing, storming past factory Nortons like they were stood still. Only the fact that DKW failed to procure the best riders prevented the company from taking the 350 world title from the dominant Moto Guzzis.
The triple – with two upright outer cylinders and horizontal middle cylinder – was another clever design but in fact originated as a parallel 250 twin. The 250 wasn’t competitive, so engineers added the extra prone cylinder. With a little development work, the beautifully compact engine produced 45 horsepower and could carry its rider to 140mph. The triple might yet have won the 350 title, but for poor management by DKW bosses who, as a result, shut down their racing department at the end of 1956.
Three decades later, soon after the DKW marque disappeared for good, the world was reminded of the company’s genius engineers when Honda unleashed its superb NS500 Grand Prix bike. The three-cylinder two-stroke unashamedly copied the layout of the DKW and in 1982 secured Honda’s first world title in motorcycling’s premier class, beating Yamaha’s faster but more unwieldy four-cylinder machine.