| MODEL | BMW R 20 1937 - 1938 |
| Year | 1937 - 1938 |
| Engine Type | Four stroke, single cylinder, pushrod operated OHV, 2 valves per cylinder |
| Displacement / Capacity | 192 cc / 11.7 cu in |
| Bore X Stroke | 60 x 68 mm / 2.36 x 2.68 in |
| Compression Ratio | 6.0:1 |
| Cooling System | Air cooled |
| Max Power | 6 kW / 8 hp @ 5400 rpm |
| Max Torque | — |
| Ignition | Battery ignition |
| Induction | 1 x Amal M 74/428 carburettor |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 3 Speed, hand and foot change |
| Clutch | Single plate, dry |
| Final Drive | Shaft |
| CHASSIS SPECS | |
| Frame | Bolted tubular steel twin loop frame |
| Front Suspension | Telescopic fork |
| Rear Suspension | Rigid, sprung saddle |
| Front Brakes | 160 mm drum |
| Rear Brakes | 180 mm drum |
| DIMENSION SPECS | |
| Overall Length | 2000 mm / 78.7 in |
| Overall Width | 800 mm / 31.5 in |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | 1330 mm / 52.4 in |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | 130 kg / 287 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.00 x 19 |
| Rear Tyre | 3.00 x 19 |
| FUEL SYSTEM | |
| Fuel Capacity | 12 Litres / 3.2 US gal |
| Fuel Consumption | — |
| Top Speed | 95 km/h / 59 mph |
The R 20 replaced the R 2 in 1937 as BMW's entry model for the licence- and tax-free class under 200 cc. It was BMW's first motorcycle with a bolted tubular frame instead of pressed steel, and it brought a telescopic fork to the small single, though the rear stayed rigid. Its run was short: new German licence rules in 1938 removed the advantage of the 200 cc class, and BMW replaced it with the 247 cc R 23.
