BMW Motorcycles: The Name equals Change. Part I

Ever wondered how BMW motorcycles get their names? The history of the nomenclature for aero engines, motorcycles and cars is marked on the one hand by enduring lines, and on the other by surprising twists and turns. As the company started out building aero engines, it was ancient history that provided BMW with the inspiration behind the naming of the first ones. The German Imperial Flying Corps arranged the engines for its aircraft according to output classes using a system based on Roman numerals, and the majority of engine manufacturers adopted this military coding for their product designations. The company used this naming system for both its water-cooled and air-cooled aero engines up to 1932 – from the ‘BMW IIIa’ to the ‘BMW XV’.

However, this military-inspired nomenclature sat rather awkwardly with the power units developed by the BMW engineers for cars and motorcycles. Instead, these engines were given the name ‘Bayern-Motor’ as a sales designation, usually followed by the output figure. A new designation system for these units was agreed within the company based around their technical fundamentals, such as the number of cylinders, their model series and project number.

This produced designations like ‘M4A1’ and ‘M2B15’, which looked decidedly secretive at first glance. Broken down, however, it was immediately clear to the initiated which product they referred to. The ‘M’ stood for ‘Motor’ (engine), the following figure for the number of cylinders, the letter for the model series and the final number for the project number in question. For example, the ‘M4A1’ was an ‘A’ series (large-capacity in-line) four-cylinder engine with the project number 1.

To be continued....