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In 1939 Georg Meier was the first foreign rider on a foreign motorcycle to win the Senior TT on the Isle of Man. His BMW flat-twin with integrated superchager could not return to the post-WWII Grand Prix scene but kept on winning German championships until the end of 1950.
“Ever since my ride in the Six Days Trials in 1926 in England I wanted to be faster than the British. I succeeded in the end but it took much longer than expected and I had to add a supercharger to the engine,” related Rudolf Schleicher to the author, about 20 years ago. A keen rider himself, Schleicher ended his career early to lead motorcycle development at BMW and was appointed technical director in 1931.
Racing success for the Munich-based manufacturer then was limited to the national scene with the flat twins in their 500cc and 750cc ohv versions significantly less powerful compared to the Best of British – single-cylinder engines and riders alike – sweeping the Continental races with few exceptions. Increasing engine output by fitting a supercharger was almost mandatory in top-class automotive sports of the time and BMW chose the same route for attacking the World Speed Record for motorcycles. In 1929 Ernst Henne left his first mark at 134.78mph and went on to 173.68mph in 1937, unbeaten for another 14 years.
BMW Kompressor Factory Racer
Year of manufacture 1939 (1949)
Engine type dohc flat-twin
Capacity 494cc
Bore x stroke 66 x 72mm
Output 55bhp (75) @ 7000rpm
Compression ratio 5:1 plus 15-20 psi boost
Carburettor Amal TT 27mm
Ignition Bosch magneto
Gearbox BMW 4-speed
Final drive shaft and bevel gears
Frame double loop
Suspension BMW telescopic front forks, rear plungers
Tyres 3.00 x 21 front, 3.50 x 20 rear
Brakes 200mm sls front and rear with cable coupling
Tank capacity 4.8 gallons
Seat height 30in
Wheelbase 80.9in (82.5)
Weight 302lb (weigh-in TT 1939)
Top speed 125mph (135)
The debut of the new BMW Kompressor (German for supercharger) was scheduled for the Avus race in Berlin on 18 May 1935. The engine with magnesium-alloy crankcase and gearbox shell was mounted in a brand-new double-loop frame welded from conical drawn oval section steel tubing. Added were a set of telescopic front forks, first tried by BMW a year before and with their hydraulic damping system, a real novelty in itself. The works BMWs showed competitive speed potential well into the first half of the European season in 1936 but still hit teething troubles until they beat the hitherto unapproachable works Norton team fair and square for the first time on 30 September at the Swedish Grand Prix at Saxtorp. The finishing order was Otto Ley (BMW), Karl Gall (BMW), Jimmy Guthrie (Norton) and John ‘Crasher’ White (Norton).
More international winning followed in 1937, with plunger rear suspension now added to the frame. New member of BMW’s road racing squad in 1938 was 28-year-old Georg Meier, who had gained some fame in Germany through his success in long distance and two days trials. With four Grand Prix wins (Spa, Assen, Sachsenring and Monza) he won the European Championship. The new German superstar was offered a place in the Formula 1 team of the Auto Union group for the following season but agreed to do at least the TT for BMW. On 16 June 1939 he won the Senior TT and fulfilled Herr Schleicher’s ambition of 13 years before. Meier again won at Assen and Spa in 1939 and was in the lead at Saxtorp when a crash resulted in severe back injuries for the daring German.
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