The Mercedes-Benz W03 was a large six-cylinder-engined automobile introduced as the Mercedes-Benz 12/55 PS and, initially, as the Mercedes-Benz Typ 300, by Daimler-Benz at the Berlin Motor Show in October 1926. It was developed in some haste under the manufacturer's Technical Director, Ferdinand Porsche in parallel with the smaller Mercedes-Benz W 01 (which never progressed beyond the prototype stage) and the two-litre-engined Mercedes-Benz W02 following the creation of Daimler-Benz, formally in July 1926, from the fusion of the Daimler and Benz & Cie auto-businesses.[1]
Naming conventions
The manufacturer applied the widely followed German naming conventions of the time. On the Mercedes-Benz 12/55 PS the “12” defined the car's tax horsepower, used by the authorities to determine the level of annual car tax to be imposed on car owners. The “55” defined the manufacturer's claims regarding car's actual power output as defined in Horsepower. In Germany tax horsepower, which had been defined by statute since 1906, was based on the dimensions of the cylinders in the engine.
Unlike the systems used elsewhere in Europe, the German tax horsepower calculation took account both of the cylinder bore and of the cylinder stroke, and there was therefore a direct linear relationship between engine size and tax horsepower.
The model was upgraded in 1927 and effectively relaunched in 1929, benefiting from the attentions of