Thingiverse
Electronic shifting servo mount (cable-actuated) by aiber
by Thingiverse
Last crawled date: 4 years, 8 months ago
This was a failed design for an electronic shifting project I was working on. It's a mount plus other stuff for a standard servo to mount to the driveside chainstay of a bike & use it to actuate the rear derailleur using a standard shift cable.
It is used in addition to the user's current RD.
We tried this with the highest torque servo we had (about 20 kgf cm, I think), & it was far too weak for a double spring old Shimano 105 rear derailleur. I think we tried with more modern long cage Shimano Claris RD (single spring) & it still was too weak.
Incidentally, many months after I designed this, this appeared:
https://www.kickstarter.com/projects/1598276649/xshifter-worlds-first-universal-wireless-smart-shi
http://www.xshifter.com/
Which mounts similarly, & actuates similarly. I haven't played with them & 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.
It is used in addition to the user's current RD.
We tried this with the highest torque servo we had (about 20 kgf cm, I think), & it was far too weak for a double spring old Shimano 105 rear derailleur. I think we tried with more modern long cage Shimano Claris RD (single spring) & it still was too weak.
Incidentally, many months after I designed this, this appeared:
https://www.kickstarter.com/projects/1598276649/xshifter-worlds-first-universal-wireless-smart-shi
http://www.xshifter.com/
Which mounts similarly, & actuates similarly. I haven't played with them & 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.