BMW R 35

BMW never made many shaft-driven, single-cylinder motorcycles. Indeed, you can count the models on the fingers of two hands. Starting with the first model, the 250cc 1925 R39, there came the R2 series, the R35 (shown below), the R20, the the R24, R25 series, the R26, and the final model, the R27. All except for the R2, R4, and R35 were 250cc models, essentially half of a boxer twin turned upright.



Dates: 1937 - 1940

Number sold 15,386

Price 955 RM

  Above — Here is a photo of a 1938 BMW R35 in the Arizona desert.

Click here to see an original R35 brochure.

Description by BMW Mobile Tradition's Historical Archives:

After the R 3 with its 300-cc engine had enjoyed very little commercial success, BMW introduced a new single-cylinder model in 1937, the R 35. Its engine was derived from the 400-cc R 4, but by reducing the bore the displacement was decreased to 350 cc. The R 35 also developed 14 horsepower and like the R 4 had a top speed of 100 km/h. The suspension had in the meantime been modernized. The frame was still made from massive-looking pressed steel sections but the antiquated leaf spring at the front was now replaced by a modern telescopic fork. In contrast to the exclusive “Boxer” models, however, there was no hydraulic damping.

The R 35, which cost almost 1000 Marks, was used in particular by the police and the military authorities both as a training vehicle and for despatches. With over 15,000 sold by 1940, BMW again had a model in its program to match the R 2 and R 4 for turnover.The R 35 was the last model that BMW produced with a pressed steel frame. The “Boxers” and the single-cylinder models now took advantage of the lighter tubular frames.

After the war, the R35 saw something of a renaissance when production was restarted in Eisenach from remaining stock. Over 80,000 of the post-war BMW or EMW (Eisenach Motor Works) R35 and the follow-up R 35-3 model (with rear suspension) were produced by 1955. Some two-thirds of these motorcycles remained in their country of origin and were used in particular for state authorities' fleets. The largest proportion of exports was to the Soviet Union and to the neighbouring Eastern Block countries. Some 5,000 bikes were delivered to Western Europe as a means of generating foreign exchange, but of these only seven remained in West Germany.

If production in Munich and Eisenach is added together, some 100,000 motorcycles were produced between 1937 and 1955. This would make the R35 the most successful model in BMW's motorcycle history.


Engine

Internal Designation M 69 und 235
Engine type four-stroke vertical single cylinder engine
Bore/stroke 72 x 84 mm
Cubic capacity 342 cm3 / 21 in3
Max power 14 PS (HP) at 3500 rpm
Compression ratio 6.0 : 1
Valves per cylinder ohv
Carburation system 1 carburettor Sum CK 3/22
Engine lubrication forced-feed lubrication
Oil pump gear pump

Power transmission

Clutch single discs, dry
Number of gears 4
Shifting manual
Gear ratios 3.4 / 2.18 / 1.35 / 1.1
Rear wheel ratio 1 : 5.63
Bevel/crown wheel 8 / 45 teeth

Electrical system

Alternator Bosch RD 47/70 2800
Ignition battery ignition
Spark plugs Bosch DM 175 T 1 or Beru K 175

Suspension

Designation 235
Type of frame Preßstahl-Doppelschleifenframe
Front suspension telescopic fork
Rear suspension rigid
Wheel rims 3 x 19
Tires front 3.5 x 19
Tires rear 3.5 x 19
Brakes front drum brake Ø 160 mm
Brakes rear drum brake Ø 160 mm

Dimensions and weights

Length x width x height 2000 x 800 x 950 mm
78.7" x 31.5" x 37.4"
Wheel base 1400 mm / 55.1"
Ground clearance 114 mm / 4.5"
Tank capacity 12 l / 3.17 gallons
Unladen weight, full tank 155 kg / 342 lbs.
permitted loading 200 kg / 441 lbs.
Fuel consumption ca. 3 l / 100 km
ca. 78 MPG
Oil consumption ca. 1 - 2 l / 1000 km
Top speed 100 km/h / 62 MPH


Below: The 250cc 1925 R39 was the first BMW single.

Below: A 250cc 1964 R27 is an excellent example
of the last of the shaft-drive BMW singles.