Engineered by NSU for the sport motorcycle segment, the 1939 NSU 501 OSL features a 494 cc (30.1 cu in) air-cooled single cylinder, four-stroke configuration. In factory specification, peak output is rated at 22 HP (16.1 kW) at 5,150 rpm. With a specific output of 44.5 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.
On the scales, the 501 OSL measures 150 kg (331 lbs) dry, translating to a power-to-weight ratio of 0.15 HP/kg (6.82 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,420 mm (55.9 in) wheelbase engineered for balanced agility and highway composure.
Within MotoLibrary's NSU archive, this model family spans 5 indexed model years from 1935 to 1939, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
