Tag Archive for 'krad'

kl. K. Kw. (Sd. Kfz. 2): Motorcycle Tractor

Kettenkrad - kl. K. Kw. (Sd. Kfz. 2): Motorcycle Tractor

The invasion of Crete (1941) revealed for the first time the use by the Germans of the motorcycle tractor. This vehicle, which retains the standard front wheel and handle bars of a normal motorcycle with the rear wheel replaced by two caterpillar tracks, is used primarily for towing light guns and supply, trailers, and for carrying dispatches in localities where difficult terrain precludes the use of wheeled vehicles. The mobility of this vehicle is as good as most tanks and its ability as a light prime mover, because of its wide gear selection, is excellent. Without load attached it has a maximum speed of 45 m.p.h. on level ground, and is capable of climbing 60 per cent grade.

The chassis is a boxlike structure of pressed steel in two sections, welded together in a horizontal plane below the track guards. It contains the driving compartment, engine, and a transverse seat accommodating two men facing the rear. A hand rail is provided on each side of the back. The driver is seated on a saddle seat directly above the transmission and clutch housing. Gasoline tanks are mounted on each side and, together with the battery and tool compartments, make up the side walls of the vehicle.

Power is furnished by the centrally mounted Opel Olympia 4-cylinder, water-cooled gasoline engine developing 37 gross B.H.P. in a displacement of 91.5 cu. in. Cooling is accomplished by a radiator, with a shaft-driven fan coupled to the crankshaft, at the rear. Six forward and two reverse speeds are available.

The suspension consists of four straddle-mounted, rubber-tired bogie wheels on torsion bars, a front driving sprocket, and a rear idler. The inner bogie wheels are of the hollow-spoke type while the outer wheels are of the removable disk type. The track, made up of 40 links per strand, is equipped with needle bearings and replaceable rubber pads.


Weight         3,400 lb. (combat)
Weight 2,700 lb. (empty)
Length 9 ft., 10 ins.
Width 3 ft., 3 1/2 ins.
Height 3 ft., 11 ins.
Ground clearance 9 ins.
Tread centers 2 ft., 8 ins.
Ground contact 2 ft., 8 ins. (approx.)
Width of track 6.7 ins.
Pitch of track 4 3/4 ins.
Track links 40
Fording depth 20 ins. (approx.)
Theoretical radius of action
     Roads 155 miles
     Cross-country 100 miles
     Road 45 m.p.h.
     Cross-country 25-30 m.p.h.
Trailer load 980 lb. (normal weight)
Size of front tire 3.50 x 19
Engine Opel, 37 hp.
Transmission 3 speeds forward, 1 reverse with high and low range
Steering Controlled differentially, mechanical brakes
Crew 2 (driver and helper)

German: p. 50

s. Krad: Heavy Motorcycle with Sidecar

WW2 Motorcycle - s. Krad, Heavy Motorcycle with Sidecar

The motorcycle, due primarily to its economy of operation, has received extensive development in Germany. The following manufacturing types are known to exist: Ardie, B.M.W., D.K.W., Horex, U.S.U., Phänomen, Puch, Standard, Tornax, Triumph, Victoria, Zundapp, and C.S. (Czech). The vehicle described herein is the B.M.W. Its outstanding operational features are: (1) a shaft final drive instead of a chain drive; (2) sidecar wheel-drive arrangement; (3) high and low range transmission, and (4) hydraulic brakes. Its average road speed is 55 m.p.h.; maximum speed, 75 m.p.h.

The frame and fork are made of pressed steel. The wheels are spoked and have dismountable axles in front and rear. The front, rear, sidecar, and spare wheels are all interchangeable.

The vehicle is powered by a 2-cylinder, air-cooled engine rated 25.4 horsepower at 3900 r.p.m. It weighs 192 pounds, has a bore of 3.07 inches, and a displacement of 45.5 cubic inches. The ignition system is the Noris type ZG 2A with automatic spark control. Full-pressure lubrication is provided. The capacity of the gasoline tank is 6 1/3 gallons.

The power train includes the single dry disk clutch, the synchromesh transmission of four speeds forward and one reverse with high and low range, and the final shaft drive with bevel gear reduction of 5.69. In order to make the cycle and sidecar combination more capable of cross-country operation, the sidecar also drives. As the drive comes back from the transmission, it enters the rear gear case by means of a shaft mounted parallel to the direction of motion. The rear wheel of the cycle is driven by means of a ring and pinion gear. However, the wheel is not on the same center as the ring gear, a pair of spur gears being mounted between the ring and the wheel to afford a further gear reduction. This gives the wheel an offset of about 4 inches to the rear of the ring gear. From the right of the ring gear the drive passes through a differential to the sidecar wheel.

The rear and sidecar wheels have hydraulic brakes; the front wheel mechanical brakes.


Weight         900 lb. (with sidecar)
Maximum load 1,000 lb.
Length 8 ft., 4 ins.
Width 5 ft., 10 ins. (with sidecar)
Height 3 ft., 4 1/4 ins.
Ground clearance 6 ins.
Suspension 3 spoked, interchangeable, pneumatic-tired wheels
Wheel base 4 ft., 9 ins.
Size tires 4.50 x 16
Fording depth 13 ins.
Theoretical radius of action
     Roads 190 miles
     Cross-country 100 miles
     Roads 55 m.p.h. (average)
     Cross-country 20 m.p.h. (average)
Engine Bayrische Motorenwerke, 2-cyl., 25.4 hp.
Transmission Synchromesh—4 forward speeds, 1 reverse, with high and low range
Crew 2

German: p. 58