Motorworld’s newspaper № 27
Test-drove video
The BMW R66 motorcycle was first presented to the general public at the 1938 salon in Berlin, together with three more BMW models: R51, R61, R71. The distinctive feature of all shown BMW motorcycles was the use, for the first time in BMW history, of telescopic rear suspension.

BMW R66 (a page from the 1939 catalog)

Model R66 was acknowledged to be one of the most advanced among the pre-WWII BMW models. Its twin-cylinder horizontally-opposed engine with the rating of 30 h.p. made it possible to achieve speeds of up to 145 km/h. Besides, the engine featured great pull, did not overheat and would start in any season with no problems (this was the achieved by using Bosch RD 50/6 2800 RS 17 generator and Bosch W225 T1 plugs for this model).

The R66 engine design was more elegant than that of the touring model R61. It also emphasized the racing aspect of using this motorcycle, even though it was also produced complete with the sidecar (in part due to safety considerations). At the time, maximum authorized speed on German autobahns was 55-60 km/h, and, compared to that, R66 characteristics seemed phenomenal. However, tyres were not good for speeds, which the R66 could achieve “solo”, and thus riding the roads on R66 without the sidecar would mean risking one life.

In 1938 preparations for the future military engagement were proceeding in full swing, and this resulted in a shortage of materials. Thus, model R66 (just as its predecessor, model R5) did not have any chrome-plated parts.

BMW R5, “Motorworld by V.Sheyanov” collection

BMW R61, “Motorworld by V.Sheyanov” collection


Model R66 did not enjoy a big success among the clients who preferred R51, which had a smaller rating (24 h.p. at 5600 rpm), but was cheaper to buy. Those who had a need in using a motorcycle with a sidecar would rather choose model R71 that was acknowledged to be a more reliable machine (even though not as technically advanced as R66).

Model BMW R66 became one of the first victims of the program started by Colonel Adolf von Schell in order to drastically reduce Wehrmacht’s spending for manufacturing its transportation means. Between 1938 and 1941 only 1669 units of this model were produced.

Manufacturer Bayerische Motoren Werke, AG (Germany)
Years of manufacture 1938-1941
Quantity produced, units 1 669
Price 1 695 RM
Today’s value 10 956 $
ENGINE AND TRANSMISSION
Type Twin-cylinder, horizontally-opposed
Engine capacity, cc 597
Bore and stroke, mm 69,8 х 78
Engine rating 30 h.p. at 5300 rpm
Sparking Battery type
Carburetor 2 carburetors, type Amal 6/420 S
Battery 6 V
Clutch Single-plate, dry
Transmission 4-speed
FRAME AND WHEELBASE
Frame type Duplex tubular, steel
Front suspension Telescopic
Rear suspension Telescopic
Brakes Drum type
Wheel size 3,50х19
DIMENSIONS
Length, mm
2 130
Width, mm
    815
Height, mm
    960
Wheelbase, mm
1 400
Ground clearance, mm
    120
Seat height, mm
    720
Mass, kg
    210
Gas tank size, l
     14
Maximum speed, km/h
    145
Range, km



Books:

PDF

Exploitation guide BMW R 51, R 61, R 66, R 71 (ger.)