- Model series breaks with pre-war traditions in formal and technical respects
- Continuous model refinement permits a long lifespan
- A unitary body design becomes the first Erlkönig – the name used by the automotive industry for prototypes
At its launch in August 1953, the new Mercedes-Benz represented a formal and technical break with pre-war traditions. These were the traditions that had moulded the 170 family, along with the 300 and 220 models. The W 120 was now the first Mercedes-Benz car to feature a three-box design with self-supporting chassis/body structure, known in Germany as the “Ponton.” Characteristic of the three-box principle, first realised in a body in the USA in 1946, are fully integrated wings, a rectangular body outline, and the almost square-hewn shape of the front end, the passenger compartment, and the rear end. At the same time, the concept allowed for reduced wind resistance (resulting in less wind noise and improved fuel consumption), as well as an appreciably more spacious interior.
The 180 model became a basis from which Mercedes-Benz derived further vehicles in the upper mid-size category with petrol and diesel engines, and starting in 1954 also the luxury saloon of the 220 family (series 180 and 128 with six-cylinder engines) and the 219 model (W 105). The 190 SL sports car presented in 1955 was also a variant of the three-box Mercedes-Benz 190 Saloon (W 121), which was developed by Mercedes-Benz at the suggestion of US importer Maxi Hoffmann.
Whereas the 190 SL had an independent body, design of the luxury cars closely followed that of the 180. The 220 a and its successors were basically distinguished from the upper mid-range model by a longer wheelbase (2.82 metres instead of 2.65), a longer front end, and six-cylinder power plants instead of the four-cylinders of the 180 and 190 models. This concept of a standard body was also retained by the Stuttgart brand for the subsequent generation of “fintail” saloon models.
For the first time in the history of Mercedes-Benz passenger cars, the 180 had a body designed as a self-supporting unit. The metal panels of the body were solidly welded to the frame-floor system with which it formed a single structural unit. Compared to the conventional design, which consisted of a body mounted on a frame, this design increased torsional stiffness at the same time as reducing weight. The 180’s design characteristics made it an ultramodern automobile of its day. The new saloon received an enthusiastic verdict from the experts.
The chassis was also improved on certain points. Compared with the 170 Sb, the front wheels, located by double wishbones, were now no longer attached directly to the frame, but to a so-called subframe. This was a U-shaped axle carrier, welded together from two pressed metal parts, and to which not only the front suspension, but also the engine, transmission and steering were attached. The subframe was mounted to the front section of the frame by means of three noise-reducing silent blocks. The rear suspension made use of the tried and tested swing axle, but now additionally had the two wheels located by radius rods set far apart.
1954: Diesel drive in the “Ponton”
In January 1954, the 180 D model was added to the 120 series. This subsequently turned out to be the most successful of the four-cylinder “Ponton” models, with almost 150,000 units being built in total. The model was especially popular among taxi drivers. Apart from the diesel engine adopted from the 170 DS, the 12-volt on-board electrical system and a modified rear axle ratio, the saloon with the prechamber diesel OM 636 VII (29 kW/40 hp) was identical with its petrol-driven sister model, that model being powered by the 38 kW (52 hp) M 136 VII L-head petrol engine borrowed from the 170 Sb.
The two models of the 120 series was given a new rear axle in September 1955. This single-joint swing axle with low pivot point had been introduced one-and-a-half years earlier in the 220 a model. This made for improved handling characteristics owing to smaller changes in track and camber.