9100 rear mech refuses to go into the smallest cog

Choddo
Choddo Posts: 16
edited April 2019 in Workshop
Hi

I've been using this derailleur for the best part of a year. It's fantastic, but last week after a few fairly messy rides (one of which I didn't clean the bike for a week) I noticed it wasn't dropping into the smallest cog any more.

There's definitely a gap to the limiter, I can pull it manually out to the longest gear, but it's like there's some kind of friction somewhere stopping the spring from doing it by itself.

Tried cleaning it as well as I can in all the pivot joints. Hasn't been knocked. Anyone have any ideas how to pin down the problem?

(got a long downhill stretch on a TT on Sunday where I'm going to look like a hamster if I can't fix this)

Cheers!

Comments

  • timothyw
    timothyw Posts: 2,482
    If you unclamp the cable does it drop down into the bottom gear? That would rule out friction in the cable run.
  • Choddo
    Choddo Posts: 16
    TimothyW wrote:
    If you unclamp the cable does it drop down into the bottom gear? That would rule out friction in the cable run.

    Aha! Didn't expect that to be a factor because they're internally routed and the only exposed cable run is so tiny, plus the little sleeving on the ferrule looked like it was working well, but that did work. Must have dragged some grime in there.

    Guess a full new cable is in order... bar tape was looking grubby anyway...

    Thanks!
  • champson
    champson Posts: 57
    From memory the 9100 cable outer from frame to derailleur is a special type.
  • Choddo
    Choddo Posts: 16
    champson wrote:
    From memory the 9100 cable outer from frame to derailleur is a special type.

    Correct. It seems to be a bit more flexible or something. I had to order some from Taiwan as they weren't available standalone in the UK, as far as I could find. The full DA cable kit includes it of course.
  • keef66
    keef66 Posts: 13,123
    Replacing the cable seems a bit extreme. Can you not try just cleaning and lubing that final bit?
  • Choddo
    Choddo Posts: 16
    Yeah good point, I'll try that first (Some kind of dry lube or won't it clag up?)

    Always like an excuse for a bit of new gear though ;)
  • keef66
    keef66 Posts: 13,123
    You'd kick yourself if you went through the faff of a new inner cable and possibly redoing bar tape only to find it was still sticking because of a bit of muck in that final bit of outer. I'd take that off and flush it out first.

    Never had anything as refined as DA so I have no idea what lube might be appropriate.
  • champson
    champson Posts: 57
    If cleaning and re-grease fails, I found the info (from the shimano manual):
    Use the OT-RS900 cable and a cable guide for smooth operation.
    Grease the inner cable and the inside of the outer casing before use to ensure that they slide properly.
    Do not let dust adhere to the inner cable. If the grease on the inner cable is wiped off, the application of SIS SP41 grease (Y04180000) is recommended.
    The end of the outer casing which has the sealed outer cap (aluminum type) should be Derailleur side on the derailleur side. For details refer to the dealer's manual for ST-R9100.

    I bought mine from here:
    https://www.hibike.com/shimano-dura-ace ... fffd69d451
  • Matthewfalle
    Matthewfalle Posts: 17,380
    just fit a new cable inner and outer and its done - job jobbed.
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • Choddo
    Choddo Posts: 16
    Thanks champson. I might pick up some of that grease. I can see why they recommend greasing that casing because the aluminium ferrule was locked in tight when I tried to pull it apart.

    Think I found the culprit. Cable frayed half way through inside the shifter! Kind of no choice about the remedy, it turns out.
  • Matthewfalle
    Matthewfalle Posts: 17,380
    you should grease all metal ferrules - basics, innit
    Postby team47b » Sun Jun 28, 2015 11:53 am

    De Sisti wrote:
    This is one of the silliest threads I've come across. :lol:

    Recognition at last Matthew, well done!, a justified honour :D
    smithy21 wrote:

    He's right you know.
  • keef66
    keef66 Posts: 13,123
    It's reassuring to know that it isn't just my 5600 shifters eating cables.

    (I really should check them; it's been a while...)

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