2

It looks like the ratchet mechanism broke in one of my shifters. As I try to shift the bit holding the end of the cable stays put and does not follow the lever. Even when it moves I can then pull by the cable and it then goes back to its starting position.

Here is a video showing what's happening.

It happened while I was cycling and I was left with only the smallest cog. There was a sound of something breaking and at first I thought the cable snapped. But it could have been the sound of the pawl breaking somewhere inside as I was trying to shift to a larger sprocket.

I was wondering how much work is replacing the mechanism and whether this can be done at all (assuming I can find another shifter to salvage the part from)? Or does the whole shifter need replacing?

enter image description here enter image description here

5
  • 2
    What do you see happening when you try shifting with the cover removed? If you could post a video, that would help immensely. And FWIW, if you find a working shifter for replacement parts, instead of taking apart both shifters trying to fix the broken one, just remove your broken shifter and replace it in its entirety with the working one. Jun 2, 2022 at 20:17
  • It's dark now so I'll try to describe it better. Top photo, before the lever was moved. Bottom photo, the lever was twisted all the way, but the cable anchor stays where it was (it should've rotated a bit with every 'click'). What looks like a little cogwheel to the left of the bit holding the anchor does rotate and there is the familiar clicking sound when the lever is being turned. Sometimes the whole thing gets jammed and the lever cannot be moved but with a bit of force can be put into motion again. The small lever for releasing the cable moves but does nothing, no clicks. Jun 2, 2022 at 20:53
  • You mentioned that it is clicking like it normally would. If you didn’t I would assume that The grease had gunked up and the pawls were not moving freely (common occurrence). Other possible cause: a worn out cable that is starting to fray. The shards of cable can break loose and get into the shifter mechanism, which can cause a whole bunch of problems like what you are experiencing. Pull up the hood on the shifter and inspect the other side where the cable enters the shifter.
    – Ted Hohl
    Jun 2, 2022 at 23:54
  • Cables breaking at the head on these is pretty common. It would be good to rule that out first. Jun 3, 2022 at 4:09
  • The cable is in good condition. It was removed and checked, you can see it in the picture dangling behind the shifter. I have now added a link to a short video in the description. Jun 3, 2022 at 13:14

1 Answer 1

4

In theory it’s possible to disassemble the mechanism, but nobody does that.

  • Shimano do not distribute spare parts, the brifter is viewed as a single unit (cf. shimano’s attitude to hydraulic calipers)
  • The mechanism is very fiddly and consists of a surprisingly large number of parts
  • If you had a working shifter to cannibalise parts, you would be better off to swap the whole brifter unit.

You could try taking yours apart to see if you can do anything to make the situation better. If it ends up even more broken, you would still need another shifter anyway.

NB if you move to 4700, you will need the derailleurs too as the actuation ratio has changed.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.