R57

Start of Production

1928

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End of Production

1930

Numbers Produced

1,005

Price

1,850 RM

Engine

Internal Designation

M 56

Motor Type

Four-stroke two cylinder flat twin

Bore x Stroke

68 x 68 mm (2.67 x 2.67 in)

Displacement

494 cc

Max Power

18 hp at 4,000 rpm

Compression Ratio

5.8 : 1

Valves

OHV

Carburation System

1 carburettor, Type BMW Spezial two valve 24 mm

Engine Lubricating System

Forced feed lubrication

Oil Pump

Gear pump

Power Transmission

Clutch

Single plate, dry - two plates from engine No. 70889

Number of Gears

3

Shifting

Manual

Gearbox Ratios

2.83 / 1.55 / 1.08

Rear Wheel Ratio

1 : 4.38 (1 : 5.7 with sidecar)

Bevel/Crownwheel

13 / 57 teeth (10 /57 with sidecar)

Electrical System

Ignition System

Bosch high voltage magneto ignition

Generator

Bosch magneto generator on request

Spark Plugs

Bosch W 175

Chassis

Designation

F56

Frame

Twin loop steel tubular frame

Front wheel suspension

Plate spring, 6 laminae

Rear wheel suspension

Rigid

Wheel rims

Deep bed 19 x 3 or 21 x 2.5

Tyres, Front

26 x 3.5 on 19 x 3 or 27 x 2.75 on 21 x 2.5

Tyres, Rear

26 x 3.5 on 19 x 3 or 27 x 2.75 on 21 x 2.5

Brakes, Front

Drum brake 200 mm / 7.87 in diameter

Brakes, Rear

External shoe brake at gearing on Cardan shaft

Dimensions / Weights

Length x Width x Height

2100 x 800 x 950 mm (82.67 x 31.49 x 37.40 in)

Wheel Base

1400 mm / 55.11 in

Fuel Tank Capacity

12.5 litres / 2.74 gal / 3.30 gal US

Unladen Weight with Full Tank

150 Kg / 330 lb

Load Rating

210 Kg / 462 lb

Fuel Consumption

3.5 litres 100 Km approx. / 80 mpg / 67 mpg US

Oil Consumption

1 - 2 litres per 1,000 Km approx.

Top Speed

115 Kph / 71 mph