Shimano Patent Shows Direct Mount Electronic Derailleur

Earlier this year we covered Shimano’s patent for a wild-looking derailleur with three jockey wheels that’s intended to provide more ground clearance when used with a wide range cassette. It turns out that Shimano had another patent granted last June that’s also worth examining – one for a direct mount rear derailleur that BikeRadar recently reported on.

Digging a little further reveals a patent that was granted last week for a wireless electronic derailleur that will use that direct mount. The patent is fairly broad, and describes several possible configurations for the derailleur. it states, “The mounting portion has a mounting opening through which a central axis of a hub axle passes in a mounting state of the bicycle rear derailleur. The mounting portion includes a single joint or is free of any joint.”

It goes on to say, “It is possible to mount a battery for the electronic components of the bicycle on the rear derailleur, which may also be to power electronic derailleur control. Therefore, the battery may be accommodated at the rear derailleur or remote from the rear derailleur with a connection to the battery mounting portion.”

Exciting stuff, I know, but the gist of it is that the patent describes a derailleur that can use some form of direct mount, and is wireless and electronic. The drawings depict one version where the derailleur is mounted close to the chainstay, and the other where it uses a link that’s similar to what Shimano used when they last tried to get a direct mount system off the ground back in 2012.

Many of the aspects the patent describes apply to the e-bike specific 12-speed XT Di2 drivetrain that was launched last summer. Things like a cadence, velocity, and acceleration sensor can be used for shifting, both manually and automatically, while coasting.

Given all the hubbub surrounding SRAM’s new direct-mount Eagle Transmission derailleur, it’s not surprising that Shimano would be working on a design of their own. Don’t forget, Shimano’s no stranger to direct mount rear derailleurs; the first Saint group debuted in 2003 with an axle-mounted derailleur. One feature that differentiates the SRAM Transmission derailleur and what’s depicted in Shimano’s patents is a B-tension screw – the Transmission derailleur doesn’t have one at all, while Shimano’s design shows a screw that can be used to adjust the position of the derailleur in relation to the cassette.

Will we see a direct competitor to SRAM’s Transmission hit the market any time soon? Although it’s clear Shimano is working on all sorts of projects, I’m inclined to think that any official launches are still well into the future. We’ll just have to wait and see.