Description
The BMW R 75 has a multi-piece bolted tubular steel frame with an additional spring strut at the top of the gearbox and a telescopic fork with hydraulic damping; The rear wheel is unsprung, the sidecar has a leaf spring . The frame can be divided by means of screws, which simplifies the removal of the engine. The tires are the same on all three wheels, with off-road tires measuring 4,5 x 16 inches. Drum brakes with a drum diameter of 250 mm are installed on all wheels. The front wheel brake is operated by cable, the sidecar and rear wheel brakes are hydraulic. [ 2 ] The standard hook can be used to attach the light special trailer 1 (SdAnh 1) and other loads. The off-road vehicle has a track width of 1180 mm, weighs 400 kg and has a payload of 270 kg. Fuel consumption (tank capacity 24 liters) is 6,3 l/100 km on the road and a maximum of 8,5 l/100 km off-road. The maximum speed is 95 km/h, the continuous speed is 85 km/h and the minimum speed is 4 km/h.
The team is powered by an air-cooled two-cylinder OHV boxer engine type 275/2 with a displacement of 745 cm³ (bore and stroke each 78 mm), compression 5,8:1. The engine has two Graetzin carburetors (SA 24/1 +2) and a Noris ZG a2 magneto ignition and Bosch spark plugs (W 225 T1). The power is 26 hp (19 kW) at 4000 rpm. The torque curve is tuned for use with a sidecar. Due to the low compression ratio, the engine can also run on low-grade or synthetic fuels. The four-speed gearbox is shifted using a foot pedal or two levers to the right of the tank. It also has an off-road reduction gear (three gears) and a reverse gear that can also be shifted down. [ 11 ] The power is transmitted to the rear wheel and to the sidecar wheel; for the sidecar drive, there is a limited slip differential to the right of the rear wheel.
Although the team initially seemed to perform excellently, there were numerous engine failures at the beginning of the Russian campaign in 1941/42. The cause was the air filter, which filled with water and mud. Subsequently, in late 1942, the filter was moved under a helmet-like cover to the top of the tank, from where the air reached the carburetors via two long pipe connections. At the same time, the telescopic fork was given rubber sleeves to keep dirt away from the slide tubes.
