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Allround · 1937

R20

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MotoLibrary Score
36 /100 Commuter
Power
8 HP
Top Speed
95 km/h
Engine
192 ccm

1937 BMW R20 Technical Analysis & Specification Breakdown

Built around BMW's allround motorcycle platform, the 1937 BMW R20 relies on a 192 cc (11.7 cu in) air-cooled single cylinder, four-stroke powerplant. In factory specification, peak output is rated at 8 HP (5.9 kW) at 5,400 rpm, transferring power to the rear wheel through a 3-speed gearbox and shaft drive (cardan) final drive. With a specific output of 41.7 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 R20 measures 130 kg (287 lbs) wet (curb), translating to a power-to-weight ratio of 0.06 HP/kg (16.25 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,330 mm (52.4 in) wheelbase engineered for quick, flickable steering geometry. The 12-liter (3.2 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 95 km/h (59 mph).

Within MotoLibrary's BMW archive, this model family spans 2 indexed model years from 1937 to 1938, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.

Specific Output
41.7 HP/L
Power-to-Weight
0.06 HP/kg (16.25 kg/HP)
Engine
Displacement 192.0 ccm (11.72 cubic inches)
Engine Type Single cylinder, four-stroke
Engine Details Single cylinder, four-stroke
Power 8.0 HP (5.9 kW)) @ 5400 RPM
Compression 6.1:1
Bore x Stroke 63.0 x 64.0 mm (2.5 x 2.5 inches)
Fuel System Carburettor
Fuel Control Overhead Valves (OHV)
Ignition Battery
Lubrication Wet sump
Cooling Air
Transmission
Gearbox 3-speed
Final Drive Shaft drive (cardan) (final drive)
Clutch Dry-multiplate-cable operated
Performance
Top Speed 95.0 km/h (59.0 mph)
Chassis
Frame Type Steel-single cradlel
Front Suspension Telescopic fork
Rear Suspension Rigid
Wheelbase 1330 mm (52.4 inches)
Wheels & Brakes
Front Tyre 2.99-19
Rear Tyre 2.99-19
Front Brakes Expanding brake (drum brake)
Front Brake Ø 160 mm (6.3 inches)
Rear Brakes Expanding brake (drum brake)
Rear Brake Ø 160 mm (6.3 inches)
Dimensions & Weight
Weight incl. 130.0 kg (286.6 pounds)
Overall Height 900 mm (35.4 inches)
Overall Length 2000 mm (78.7 inches)
Overall Width 800 mm (31.5 inches)
Fuel Capacity 12.00 litres (3.17 US gallons)
Other
Starter Kick
Carrying Capacity 200kg
More from BMW
Buying Checklist

Before You Compare This Bike

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.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
Rider Profile

Who Is This Bike For?

🟢
Beginner
A2 license compatible, manageable power.
🌍
Best For
All-Round & Adventure
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