If BMW has become one of the most famous brands in the motorcycle world (and others), its history did not predestined it to become a player in the field of two-wheelers. The famous flat-twin owes its fame above all to a reversal of fortune. The world had sunk, and from a sanction the epic BMW Motorrad was born.
It was at the end of the First World War. The ban on the construction of aircraft engines imposed on Germany by the Treaty of Versailles in 1919 put an abrupt end to the series of successes of BMW, then mainly a manufacturer of aircraft engines. First, the engineers built the Bavarian engine M 4 A 12 derived from the aircraft engine IIIa to make it a stationary engine or a group intended for the propulsion of boats, tractors or trucks. The company, which at the same time was looking for new fields of activity, then turned to two-wheelers. The post-war reconstruction was indeed linked to mobility needs which were increasingly covered by motorcycles..
Engineers then developed a small engine with two opposing cylinders with a displacement of 500 cm3. As the pistons and cylinder block of the new M 12 B 15 were made of aluminum, the assembly weighed only 31 kilos. At first, BMW sold this engine to two-wheeler manufacturers. And then, in 1922, BMW decided to turn to this prosperous market as a motorcycle manufacturer..
The R 32, the world’s first motorcycle with a flat engine and drive shaft.
Starting from the existing engine, engineer Max Friz, co-founder of BMW, planned to mount the cylinders transversely to the direction of travel. The crankshaft was in a longitudinal position. The gearbox with also longitudinally arranged shafts was controlled by a friction clutch, the two housings being screwed together. The connection between the gearbox and the rear wheel was provided by a cardan shaft. Each of these basic characteristics was already present in the market. But Max Friz was the first to put them together in the innovative construction of the BMW R 32.
On September 28, 1923, at the German Motor Show, in the exhibition halls of the Kaiserdamm in Berlin, BMW officially presented its first motorcycle, in addition to its range of engines. It was a courageous act. The Munich manufacturer faced competition from more than 130 motorcycle manufacturers in its own country. At the same time, the machine powered by an 8.5 hp engine cost Reichsmark 2,200 without options, making it one of the most expensive. Its commercial success nevertheless provided proof that BMW had bet on the right concept. The BMW motorcycle was distinguished from its competitors not only by the flattened unit formed by the engine and the gearbox but also by its frame with two closed buckles of steel tubes.
parallels. The flat boxer engine placed very low significantly improved the position of the center of gravity and, at the same time, the driving characteristics. The front wheel fork only allowed low travel, but the use of leaf springs provided a certain self-damping effect. The deep black enamel varnish and expensive white line decor set standards for the quality of the finish.
The first light alloy piston motorcycle engine.
But the mechanics of this bike set even more important criteria. The early BMW motorcyclists could take pride in the fact that they benefited from the experience of the aircraft engine manufacturer. This resulted in the choice of materials as well as the use of light alloy for the pistons as well as operational safety and reliability still difficult to find in the motorcycle construction sector..
No vulnerable chain drive between engine and box, no chain or belt to the rear wheel, valve stems and springs encapsulated high on the cylinders in a dust and oil tight manner. With the lubrication circuit closed, this had the effect that the motorcycle remained clean and that maintenance operations were considerably simplified..
At that time, the best advertisement for a new motorcycle, and for a new brand in particular, was to achieve success in sports competition. Thus, on February 2, 1924, the young engineer Rudolf Schleicher took the start of the mountain race of the Mittenwalder Steig and won with the fastest time of the day in his BMW. In doing so, he made himself the first motorsport winner in the history of the Bayerischen Motoren Werke. But Schleicher was not just a fast motorcyclist. He was also an ingenious builder.
On May 18, 1924, three BMW factory test pilots started the Solitude Race in Stuttgart with a cylinder head of his design,
which was, for the first time in the field of motorcycle construction, cast in light alloy, and overhead valves (ohv) encapsulated under a cover hood. They won in three categories. This new construction was taken again in 1924 in the new sport model.,
the R 37 which, with its 16 hp, was almost twice as powerful as the R 32 at the time.
The rest is history and a succession of developments. If the brand has diversified with several types of engines and categories of machines, the foundations laid by the R32 are still present in today’s R models..
Image credit: BMW – D.R
What you must remember
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Model marketed in
medium: 3 l
about 95 km / h
The technical aspect
BMW R32 1923
- Tank: 14 liters
- Width: 800 mm
- Height: 950 mm
- Wheelbase: 1380 mm
- Operating weight: 122 kg
- Train before
- secondary by cardan
- Rear axle
(68 x 68 mm)
at 3,200 rpm