Electronic shifting servo mount (cable-actuated)

thingiverse

This was a failed design for an electronic shifting project I was working on. A mount plus other components were needed for a standard servo to be mounted on the driveside chainstay of a bike and used to actuate the rear derailleur using a standard shift cable. It is used in addition to the user's current rear derailleur. We tried this with the highest torque servo we had (about 20 kgf cm, I think), but it was far too weak for a double spring old Shimano 105 rear derailleur. We also tried it with more modern long cage Shimano Claris RD (single spring) and it still was too weak. Incidentally, many months after I designed this, something similar appeared: https://www.kickstarter.com/projects/1598276649/xshifter-worlds-first-universal-wireless-smart-shi http://www.xshifter.com/ Which mounts similarly, and actuates similarly. I haven't played with them, and I'm not sure how they got a strong enough servo/linear actuator, but they cost too much for me to find out. Since it actuates over a very short cable length with no considerable bends, the reduced friction should permit pretty good quality, if it worked. Updates 17 Dec 2016: We uploaded some PDFs and images demonstrating how the assembly comes together. Assembly & Materials We use zipties and inner tube shims to mount to the seatstay. You will need some small screws; we don't know the threading or size. An additional aluminum (sheet metal) servo mount is also needed. I think a CAD of that is provided. It came with the servo we had, so I never tried to buy one, and I don't know anything about availability.