BMW Motorcycles R50 1955
In 1955, BMW introduced the 500cc R50 and the 600cc R60 and R69, which continued the company’s preference for the well-balanced boxer twin engines and shaft drive that it had employed since 1920.
The new models featured revised front and rear suspension with Earles front suspension geometry replacing the previous telescopic design and swing arm geometry with the drive shaft mounted within the right-hand arm replacing the earlier plunger design. The Earles design addresses the problem associated with telescopic forks of diving under braking.
The 494cc OHV engine has ‘square’ bore and stroke dimensions of 68mm x 68mm and features ball bearing main bearings and roller bearing big end bearings. The compression ratio is 6.8:1. The 6-volt electrical system includes a Noris 60/90W dynamo with automatic voltage control while ignition is provided via a Noris magneto with auto-advance. It has a four-speed gearbox and tested top speed was 90mph (149kph) with a best one-way of 94mph (151kph).