There was a time that BMW was known as BFW – Bayerische Flugzeugwerke – until the Treaty of Versailles banned the company from building its 19-liter 220 horsepower, inline, six-cylinder aviation engines at the end of World War One. So superior in performance at high altitudes were those large-capacity six-cylinder engines that the two-year-old company was no longer allowed to build engines larger than 500cc.
When BMW decided to build its own motorcycles early in the 1920s,Chief design engineer, Max Friz was asked to redesign the Helios. He preferred to start with a clean sheet, and drew up a new 486cc, 8.5 horsepower boxer twin, rotated 90 degrees so that both air-cooled cylinders would benefit from the oncoming breeze. Though the layout was not completely unique to BMW as it was also used by British company ABC before, Max Friz design bristled with further innovations including the use of shaft drive. The resulting BMW R32, the first motorcycle with a self-contained lubrication system, integrated the three-speed gearbox and the engine into a single unit, and its side-valve cylinder heads were made out of alloy instead of cast-iron.
The BMW R32 also laid the engineering foundations of every R-series BMW has built since 1923, introducing a powertrain layout that is as iconic in the motorcycling areana as is the rear-engine, rear-wheel-drive transaxle format of the Porsche 911 in the sports-car world.