P practically simultaneously with In 1954, Daimler-Benz brought an omnibus onto the market, the Mercedes 300 SL gullwing. The O 321 was not only designed to look like the brand's cars; The technology also moved away from the cumbersome truck offshoot.
Lighter and up to 95 km /h
A frame floor system with a load-bearing middle section brought stability to the body and created space for it Technology and saved weight: the new bus weighed 138.5 kilograms per passenger seat. The previous model O 3500 had to carry 172.5 kilograms for each passenger. At the same time, performance increased: the six-cylinder OM 321 diesel developed 110 hp from a displacement of 5.1 liters. That was enough for a top speed of 95 km /h and is particularly impressive when you know that a 180D ran 112 km /h and a 180 gasoline engine reached a maximum of 126 km /h.
The best bus of its time
The magazine Lastauto Omnibus stated, 'that this absolutely new development is one of the best, if not the best series-produced buses in this size class currently available.' O 321 is successful In any case: in ten years the Mannheim plant will build 18,083 buses, chassis and CKD parts kits for assembly in export markets. The bus is most popular in Iran, the United Arab Republic, Turkey, Austria, Saudi Arabia and Argentina. In some countries it still dominates the streetscape for decades.
A bus for the city and for travel
Depending on where it is needed, the O 321 is available as a city bus with folding doors, as an intercity bus with revolving doors or as a long-distance coach. It has roof edge glazing like a VW Samba bus and, if desired, a sliding roof. Because of the partially load-bearing design, body builders can use the bus for their own bodies.
Practical middle carrier
The basis for this is a central support in which heating, cables and compressed air lines are accommodated. There are high side walls on the central girder that accommodate a steel profile framework. The coil-sprung front axle is connected to a subframe, and four rubber cushions keep the structure away from vibrations. At the rear, a rigid axle hangs on leaf springs under the structure in a very classic way. The developers had copied design features such as the subframe and the self-supporting construction from car design. The designers were also based on the pontoon and gullwing: the shape of the grill and the headlights are reminiscent of the brand's cars.
The developers are proud of the turning circle of just 16 meters, which is also used in turns on Alpine roads does not need to be reset. The engineers drive to the Stilfser Joch for testing, as recordings from that time show.