Shimano roller brakes: differences between each model and interchangeability One of my bikes has mounted a Shimano Roller Brake (BR-IM35 FF in my case).
These brakes on my bike are basically not working anymore and I would like to replace them (it's not a cable issue. They were already bad when I bought the bike, I've never worried about greasing them and now they are null...)

My problem is now to find which one to choose. There's more than one version but I haven't found anywhere what is the difference between them (besides the price!). For example these websites have some examples:

https://en.hollandbikeshop.com/bicycle-parts-city-bike/bicycle-brakes/shimano-nexus-brakes/nexus-roller-brake/

https://bcbikeshop.dk/rullebremser

What I can guess is that the IM denomination comes from "Inter M":
https://bike.shimano.com/en-EU/technologies/component/details/shimano-inter-m

I've found these other discussion but no answer:
Difference between BR-IM and BR-C Shimano drum brakes?

And on the Shimano website there's no information whatsoever. I've even tried the spanish, american and japanese website :D. I've found googling only some assembly drawing like this one for my brakes: http://si.shimano.com/pdfs/ev/EV-BR-IM35-FF-2776.pdf



Does anyone have any idea?! Are they still on production?



And well, if you're ending up on this discussion, you'll find some information on the might Sheldon Brown page:
https://www.sheldonbrown.com/rollerbrakes.html
For all I know the roller brake mounting mechanism is the same for all the Shimano roller brake models and all use the same cable pull ratio. 

Different (ly priced) models have different stopping power adn cooling (although none are recommended for long braking on descends etc).

Cleaning and regreasing them usually helps. Shimano roller brake grease works fine in my experience, although I suppose (haven't tested) that molybdenum disulfide grease from a store should work fine (NLGI 1 hardness seems apropriate).

Made a video showing how to dissassemble, clean and reassemble a roller brake (lubing is not shown). 

There's also a long and detailed explanation of the Shimano roller brakes on Sheldon Brown website.