A Few (Thousand) Words on BMW's Naming Scheme

The names BMW has given its motorcycles over the years seems pretty arcane from the outside. In fact, its purpose and construction has varied. Even so, it's far more comprehensible than, say, Harley Davidson's approach, which has used all but two letters of the alphabet.

For the first 60 years of BMW's history making motorcycles, all of them were named with a leading R, a number, and optionally a suffix. The R stands for rad, literally wheel, but also a nickname for a motorcycle.

The first BMW motorcycle was the R32. It seems that the meaning behind 32 is lost to history. From its introduction in 1923 until the introduction of the R11 in 1929, it seems that the first digit indicated a model generation and the second was either 2 for sidevalve or 7 for overhead valve motors. The sidevalve R11 and its OHV mate, the R16, changed that. But in 1935, the R12 and R17 replaced them, and the pattern for the second digit was restored. During this period, engine sizes were first 500cc, and then 750cc.

Singles were all OHV motors, so that pattern never applied. The first one, in 1925, was the R39, joining the R32 and R37. But there was no successor to match the R42/47 and R52/57, until the R2 appeared in 1931. With this bike, the number seems to indicate the displacement, which was 200cc. This pattern becomes clearer with the R4 (400cc), the R3 (300cc), and the R35 (350cc), reaching up to the start of WWII.

The pattern spread to the twins with the introduction of the R5 (500cc) in 1936 and the R6 (600cc). Note that the distinction between sidevalve and OHV in the model number was dropped. Next came the R51, R61, and R71 (750cc, sidevalve), which all introduced the plunger rear suspension. The final prewar twin was the 600cc OHV R66. The last new design from BMW before its factories were destroyed was the R75, a 750cc OHV model.

After the war, this well established pattern continued, but with a twist. The first twin, in 1951, was a reconstruction of the prewar R51, with a few updates, hence, the R51/2. The next year this idea was carried further when a completely new motor replaced the prewar design and the R51/3 was introduced. An R67 came out, succeeding the old R66, then an R67/2. And a sports model, the R68. Both were 600cc. The next generation of twins came out in 1956, the R50, R60, and R69. In 1961 these models were all updated, creating the R50/2, R60/2 and the R69S (for Sport). The singles, all 250cc, followed suit: R24, R25, R25/2, R25/3, R26 and finally the R27.

These "slash" numbers took over in 1970, with the introduction of the /5 series: R50/5, R60/5 and R75/5. The first number was the actual displacement (divided by 10) and the slash gave the series. In 1974 the /5s were replaced by the /6s, and in turn they were replaced by the /7s in 1977.

At this point, the slashes sort of died out. succeeding years saw just the displacement. A suffix might indicate what kind of bike was intended as BMW endeavored to specialize models. RS (renn sport, or racer) with its tight, frame mounted fairing; RT (for touring) with an expanded fairing and upright seating; and S (sport) with a fork mounted bikini fairing. In 1980 came the G/S, later GS (gelaende/strasse, or dual sport).

In 1983 BMW introduced the K-bikes. K, for kompact, indicated the water cooled, longitudinal inline 4 (and 3) cylinder bikes. Otherwise, the naming followed pattern: K100 and K75 were standard bikes and the K100RS and RT gave the same idea as on the R bikes.

In 1993 BMW brought out the new generation "oilhead" twins. At this point the new R bikes and the K bikes adopted numbers that no longer divided displacement by 10. So the first oilhead was the R1100RS, and the K bikes, which saw a displacement increase, came out as K1100s.

At the same time, a new single was introduced, the first since 1967. It was as different as could be, with chain final drive, water cooling, a motor designed and built by Rotax and the bike assembled by Aprilia. These "Funduro" models were dubbed F650s.

If rumors are correct, next year will see all new R and K bike designs. Will they still be called R and K?