Press Release) For precisely 30 years, counting from the
first-ever bus built by Benz & Cie., trucks and buses developed in
parallel. Then, in June 1925, they began following different paths.
Bus bodies had previously been mounted as a matter of course on
conventional truck chassis which featured straight frames. This had
meant quite a climb for the passengers. The new “low-floor” bus,
produced in Gaggenau from 1925, ushered in a new era with a clearly
more comfortable entrance height for passengers.
This, however, required a special chassis, one with a frame off-set
downward behind the front axle to continue straight on to-ward the
rear end where an upward offset section provided space for the rear
axle. This elaborate design resulted in a floor that was merely 670
millimeters above the ground.
Lowered center of gravity with a variety of advantages
A running board
additionally subdivided the entrance into steps each a little over
300 millimeters high – this would even be quite acceptable for a
present-day regular service bus. And the low frame had a number of
other advantages. The resulting lower center of gravity improved the
buses’ handling characteristics, for instance. This, in turn,
clearly enhanced comfort as well as safety, especially the safety of
country buses with heavily laden roof-mounted luggage racks. A
contemporary brochure summed up these advantages as follows: “Due to
the low position of the body, the vehicle handles more smoothly and
rolls less than a bus with the conventional high design.”
What’s more, the buses with low frames and correspondingly lowered
bodies were not as long-legged as their predecessors and therefore
looked clearly more elegant. This visual departure from trucks
served as a highly welcome distinguishing feature in local public
transport, still a young branch of industry at the time.
Emancipation also included a dedicated long wheelbase. This, in
turn, made it possible to accommodate virtually all passenger seats
between the axles where ride is at its most comfortable. It also had
the effect that the bodywork was subjected to reduced stresses
overall. As a result, a lighter design could be adopted, “with
favorable effects on tire wear and fuel consumption,” as the
brochure informed customers in 1925.
No shortage of variants
Right from the start,
Benz manufactured several different ver-sions of the low-floor bus.
The backbones for the bodies were frames with wheelbase lengths of
5,000 and 6,000 millimeters. The vehicles were available in urban
and country bus versions as well as with different door
configurations. Last but not least, Benz & Cie. manufactured buses
for operation with conductors as well as so-called one-man buses.
The 7.3 and 8.4 meter long basic buses with model designations 2 CNa
and 2 CNb were powered by existing four-cylinder gaso-line engines
which developed 40/45 hp and 50/55 hp from dis-placements of 6.3 and
8.1 liters, respectively – sufficient power for a top speed of
around 40 km/h. According to the manufac-turer, the smaller engine
consumed 18 kilograms and the larger one 26 kilograms of gasoline on
100 kilometers – liters were not yet used as a unit of measurement
at the time. The 7.3 meter long bus (with 5,000 millimeter
wheelbase) carried up to 24 pas-sengers while the longer version
with 6,000 millimeter wheel-base and more powerful engine
accommodated up to 32 seats.
It goes without saying, however, that buses had not become
completely independent from truck development overnight. Even the
new offset frame was based on a truck design. A little ear-lier,
Benz had introduced the offset frame for garbage disposal vehicles
to make the trash collectors’ tough job a little easier in that they
no longer had to lift the heavy garbage bins as high up as before.