From an African site.
BMW Nomenclature History
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.
There’s no mistaking that the ‘S’ in R 1200 S stands for ‘Sport’
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.
The BMW R 32
BMW acted to simplify the system in the mid-1920s. The references to the number of cylinders and model series were abandoned. Now the only entry in front of the project number was to denote an engine ('M' = Motor), transmission ('G' = Getriebe), a frame for motorcycles ('R' = Rahmen) or a chassis for cars ('F' = Fahrgestell).
And this was how the first ever BMW motorcycle got its name. The frame for the new bike was given the project number 'R 32' when it was entered into the project list. The engine was christened 'M2B33', later shortened to 'M33'. The transmission used in the motorcycle bore the designation 'G 34'.
The internal project number for the frame construction saw the motorcycle unveiled with the official sales designation 'BMW R 32'. Initially, all the brand's motorcycles were issued with their name according to this system, a product of the design organisation. In the public use, the 'R' stands for 'Rad', a short name for Motorrad (=motorcycle) at this time. Interestingly, many mistake 'Rad' for the other sense of the word - 'wheel'!
The mid-1920s saw an enforced change to this designation principle. Up to that point each motorcycle had its own frame construction. Now the designers started using the same frame for several models, although these could be distinguished by the engine variant fitted. This development meant that the sales designation for the models could no longer be based on the project numbers for the frames. The 'R' was retained, but was now followed by a two-digit number that differed from the design designation.
The 500cc boxer unit was named the BMW ‘R 5’
Motorcycles were to be given new sales designations. A system giving the single-cylinder machines single-digit sales designations and the two-cylinder units two-digit designations was hastily introduced.
With the acquisition of the Eisenach vehicle factory in 1928 the decision was taken to separate the numbering systems for aero engine, motorcycle and car development. The National Socialist authorities oversaw an intensification of rearmament in Germany from 1933. In order to simplify the expansion of the Luftwaffe, the Reich Air Ministry apportioned fixed numbering systems to its various engine manufacturers. BMW was given the range between 100 and 199.
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'.
The GS designation has found its way onto rider clothing and merchandise
BMW got back into its stride after the end of the Second World War with further developments of its pre-war models. The first post-war motorcycle was an only slightly modified version of the pre-war single-cylinder BMW R 23. As well as breathing new life into 1930s engineering, BMW also rekindled the familiar old designation system, and the first post-war model - presented in 1948 - bore the name BMW 'R 24'. When it came to motorcycles powered by boxer engines, BMW retained the familiar designation 'R' (followed by a number denoting the engine displacement) over the course of the decades that followed.
Offshoots of the basic model were identified by added-on abbreviations: for example, 'G/S' standing for Gelände/Straße (offroad/on-road); 'GS' for Geländesport (off-road sport); and 'RT' for Reisetourer (tourer).
The decision of BMW to produce motorcycles with in-line engines saw the bikes in these model series receive a totally separate designation. The development designation 'K' was adopted as a series badge. As with the boxer models, the 'K' was followed by a number derived from the displacement of the in-line engine. BMW followed the same pattern with the single-cylinder machine that went on sale in 1993. This model series was given the designation 'F', referring to the 'Funduro' concept. More recently, the new generation of lightweight single-cylinder machines presented in 2006 took on the letter 'G'.
Just in case you’re in any doubt, HP stands for High Performance
BMW explored a totally different direction in its attempt to launch a new type of mobility concept. Its 'enclosed motorcycle' was christened BMW 'C1', the 'C' standing for 'City' - the main area of use for this two-wheeler. Meanwhile, the new off-road bike unveiled in 2005 saw BMW break for the first time with the naming systems used for boxer-engined motorcycles since 1923. It was dubbed the HP (High Performance) 2 (cylinders) Enduro. This range has since been expanded with the 'Megamoto' and HP2 Sport.
So what about the numerous model codes that we have also become acquainted with over the years, such as R, RS, S, CS, C, CL, GS, RT, RS, GT and LT?
The first time that 'R' was communicated was with the R 100 R of 1991. It means 'Roadster' of course. 'S' stands for Sport. It first appeared with the R 50 S and R 69 S and then again in 1973 with the R 90 S. More recently, the R 1100 S, R 1200 S and K 1200 S have proudly worn the 'S' designation.
ST stands for Street or Sports Touring
There was a BMW car model series in the Sixties called 'Coupé Sport', or 'CS'. In motorcycles, this designation was used in 1980 for the first time after the facelift of the R 100 S, but this time standing for 'Classic Sport'. It also appeared with the launch of the rotax-powered F 650 CS in 2001, but in this case, meaning 'City Scarver. The RS designation appeared for the first time at a 17-round series for production racers. On the 1939 R 51 RS, it stood for 'Rennsport' (race sport) with the 'SS' designation standing for Supersport. From 1976 the 'RS' description became known as 'Reisesport' (travel sport), and has since been joined by 'RT' (Reise-Tourer - travel tourer); 'LT' (Luxus-Tourer - luxury tourer); 'C' (Cruiser); 'CL' (Cruiser und Luxus - luxury cruiser); and 'GT' (Grand Tourisme). The 'GS' designation we know so well actually made its debut in 1980 as 'G/S' to mean 'Gelände/Straße' (off-road/on-road). There was also the 'ST', which was first used in 1982 for the street version of the GS. It stands for 'Straße/strada' (street) and can be seen on the latest R 1200 ST model.