FROM THE CLASSIC MOTORCYCLE OF AUSTRIA COLLECTION It’s rare when you can look at a motorcycle knowing absolutely nothing about it and conclude, ‘That’s amazing.’ This 1925 BMW R37 is an incredibly rare machine, but even more extraordinary is the restoration it’s received, which is beyond concours. That tracks, as the BMW R37 is perhaps the most coveted BMW ever made, being the factory’s first competition motorcycle, introduced in 1925, only two years after motorcycle production commenced. The R37 used the same chassis as BMW’s first model, the R32 of 1923, but its motor (designated M36a at the factory) was modified with steel cylinders and aluminum OHV cylinder heads, plus a beefed-up, pressed-together crankshaft with one-piece connecting rods for strength. The R37 had nearly triple the horsepower of the R32 it was based on, with 16 HP at 4,000 RPM, and won the very first race in which it was entered, at Solitude. An immediate success, the R37 showed BMW’s intentions as a manufacturer, to build high-quality, beautifully engineered motorcycles that were equal to or better than any in the world. The R37 was produced only for two years, 1925-26, and could be considered the super sports version of the R32. Only 152 machines were built, and while the chassis is the same as the R32, the engine is very special, as are details like the handlebars, exhaust pipes, extra fuel tank and an extremely rare Deuta tachometer. The M36a motor of the R37 had 494cc with overhead valves in an aluminum cylinder head, with an aluminum cylinder as well. The engine was ‘square’ with a 68x68mm bore/stroke, a compression ratio of 6.2:1 and a power output as high as 22 HP in racing trim at 4,000 RPM. The carburetor was BMW’s own complex triple-slide design, with an air slide for each carburetor as well as a general air slide for both carbs. The valves were angled at 90 degrees, with valve seats screwed into the aluminum cylinder heads. The rocker arms ran on roller bearings and were operated by steel pushrods. The cylinders and heads for the R37 were designed by Rudolph Schleicher as his first task after graduating from engineering school, under the watchful eyes of Max Friz and chief designer Marin Duckstein. Schleicher’s design was patented on December 18, 1923, and shortly after he was given the task of creating an experimental department at BMW, only one year after joining the firm. Their faith in him was rewarded with race wins and an incredibly rapid period of development for BMW models, and the first of his designs was the R37. Taking a good long look at the photos of this machine is an enjoyable pastime and reveals exactly how the machine was laid and operates, from its heel-pressure ‘dummy rim’ rear brake to that vexing triple-chamber carburetor. This 1925 BMW R37 is an apex motorcycle, and an all-time great design, as the first motorcycle that hinted at BMW’s coming dominance in speed contests and all forms of racing. S109 1925 BMW R37
