What does the /2 /5 /6 etc mean?

Hi all, I currently ride a K1600 GTL but I love the vintage BMW’s and hope to own/restore one or two when I retire in a few years.

This is a very basic question. What does the /2 /5 /6 etc mean? I thought it might be the number of cylinders but I don’t think that stacks up. Who can enlighten this newbie?

Thanks

The / numbers are simply a designation of a series of motorcycles. The /2 bikes were built prior to and including 1969. The /5 models were started in model year 1970 and continued through 1975 or '76 models. Then /6 and /7 models followed. Later BMW dropped the / designation altogether. Meanwhile, even during the / series years BMW designated some models without the slash such as the R90S during the /6 years.

There are others more expert than I am who could expand this to very specific years for each model but this is the overview of what the slashes mean. I would add that the change from /2 to /5 bikes was a major change with a complete redesign of the engine and the frame and suspension. Changes from /5 to /6 to /7 were more incremental.

Duane has a bit of discussion about the "slashes" on this page:

https://w6rec.com/what-does-2-3-5-6-and-7-bmw-models-mean/

There's a lot about it that makes sense...and a lot that doesn't! The "slash" designation generally referred to a model change. For example, before WWII there was an R51. After the war, they had to rebuild the bike from scratch, not sure how much they had in the way of drawings, but probably relied on taking apart an R51 and redesigning it...what came out was the R51/2. A few years later, there was an improved version, the R51/3.

The near-term "/2" is a little more nuanced. As Paul said, this is generally the period beginning with the 1956 models to the end of the 1969 twin cylinder models. But the use of the /2 designation didn't happen until the 1961 models came out. But it's generally thought that whole period was the /2 era.

For the twin cylinder /2 models, they all had the leading link front suspension or Earles fork. But late in the /2 era, BMW introduced twin cylinder bikes with the telescoping front end we're more familiar with. They were designation as "US" models as in R60US, not R60/2. Clearly it was a different model with the different front end. BMW was likely looking to cater to the US market but also using these front ends as a test bed for the release of the 1970 /5 which came out in late 1969.

Thank you

PGlaves said:

The / numbers are simply a designation of a series of motorcycles. The /2 bikes were built prior to and including 1969. The /5 models were started in model year 1970 and continued through 1975 or '76 models. Then /6 and /7 models followed. Later BMW dropped the / designation altogether. Meanwhile, even during the / series years BMW designated some models without the slash such as the R90S during the /6 years.

There are others more expert than I am who could expand this to very specific years for each model but this is the overview of what the slashes mean. I would add that the change from /2 to /5 bikes was a major change with a complete redesign of the engine and the frame and suspension. Changes from /5 to /6 to /7 were more incremental.

Click to expand...

Thanks for the feedback. It was one of those things that was bugging me and I really wanted to know.