BMW took the new instructions as the signal to introduce a new internal naming system.As the numbers 100 to 199 had already been assigned to aero engines, motorcycles were given the range from 200 to 299 and cars the 300-to-399 band. The existing motorcycle models were integrated into the new system according to their conventional designation. For example, in development documents the ‘R 32’ became the ‘232’. The sales designations traditionally used for motorcycles were retained, although modifications were made to the existing system. From the mid-1930s the nomenclature for the models reflected, as a rule, the engine displacement. For example, the 500cc boxer unit was named the BMW ‘R 5’ and its successor the BMW ‘R 51’.