Motorworld’s newspaper №53

In the history of the motorcycle industry the Mars brand is firmly connected to the famous A20 model which was dubbed “White Mars” due to the characteristic white color of the absolute most of these machines. The motorcycle was also available in red and green, but the minimalistic white is most associated with the model. Mars A20 is a legend among German motorcycles, so it is not for nothing that a postage stamp was issued in 1983 to celebrate the machine. The most interesting feature in this model was its engine manufactured by Maybach having a very large engine capacity (for its time) and an unusual structural design.

Mars A20

The Mars A20 motorcycle that was first produced in 1920 (under a name Reisemaschine, i.e. a vehicle for traveling) became a focus of the most cutting-edge and original technical ideas of the time. To start with, it did not have a frame in the common sense of the word. The base of this machine consisted of a box-section frame in which the gas and oil tanks were positioned as well as a carrying box. An L-head, horizontally opposed, twin-cylinder engine (with 956-cc and 7.3 h.p.) was longitudinally mounted under the frame having an external flywheel that simultaneously played the role of the fan for the forced air cooling system.

Mars A20 postmark

Next to it, a Pallas carburetor was “hung up” featuring the upcoming flow of the combustion mixture, and the intake of the warmed-up air was provided via the long junction pipe from the rear cylinder. The Mars engine got a very ingenious gas distribution mechanism: a cam shaft located in the upper part of the assembly and driven by two spur pinions from the crank-shaft was directly driving four complex-shaped crossbeams, each if which controlled its own valve.

The engine together with the box-type frame made up a single power assembly which also included the sump of the two-speed transmission. The motorcycle transmission deserves special attention: two drums with internal friction pads were located on the cross shaft. Each drum had own chain connected to the rear wheel, so there were two chain sprockets at the rear. During the gear selection one of the drums was decelerated and the torque was transmitted to the rear wheel. Band brake gears were located over the lead drums: one gear with the manual and the other with a foot control.

Mars A20 was also a sports model. Factory drivers Ernest Schulz and Heinz Wilhelm are here on White Mars motorcycles when they took the first and second prizes during Bavarian championship in 1921.

 

The engine was started with a hand crank (like in cars) using a special actuator. The wheels were made interchangeable since their flanges did not have braking mechanisms. More so, even with the single-rider option the Mars A20 could carry a spare wheel on the right side. A short leading link of a very complex design completed the look of the motorcycle.
White Mars was manufactured until 1932 subjected to constant modernization. Just over one thousand machines were produced.

 

 

Manufacturer Mars Werke, AG, Nuremberg (Germany)
Years of manufacture 1920-1932
Quantity produced, units 1 000
Price
Today’s value
ENGINE AND TRANSMISSION
Type L-head, horizontally-opposed, twin-cylinder
Engine capacity, cc 956
Bore and stroke, mm 80 х 95
Engine rating 12 h.p.
Sparking Bosch magneto
Carburetor Pallas
Battery
Clutch
Transmission 2-speed
FRAME AND WHEELBASE
Frame type Box-type carrying frame
Front suspension Short leading link, of complex design
Rear suspension Rigid
Brakes
Wheel size 3,0 х 22
DIMENSIONS
Length, mm
2 300*
Width, mm
1 800*
Height, mm
1 250*
Wheelbase, mm
1 600*
Ground clearance, mm
   130*
Seat height
   840*
Mass, kg
   155
Gas tank size, l
     10
Maximum speed, km/h
     80
Range, km

* – Data on the results of the measurement of the “Motorworld by V.Sheyanov” exhibit.