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Some of My Gears Are a Talking Kangaroo.

(9 posts)
  • Started 9 years ago by Uberuce
  • Latest reply from Uberuce
  • This topic is not resolved

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  1. Uberuce
    Member

    I upgraded to a wider cassette on my Croix late last year, which meant upgrading* to a 105 rear derailleur and chainset, but now the middle cogs are skippy when I'm in the little front ring. On the big ring for everything and with the little ring at the big and little cogs, everything's fine.

    I am running:
    105 rear derailleur; 10 speed nabbed cheap .
    Tiagra front derailleur; now two and bit years old but not many thousands of miles on it and still working fine.
    Tiagra 2x10 shifters; Same age, and until the 'upgrade' working fine.

    I suspect my chain is too long, but I'm not sure how best to determine that for sure, or whether it's even a likely culprit.

    I've also not recabled the thing ever, so there's maybe culprit 2.

    Or I need to nab a pair of 105 shifters before the 2x10 all sell out.

    I can't make the problem go away by meddling with the barrel adjuster. Halp?

    *Shh. I know it doesn't. Shh.

    Posted 9 years ago #

  2. wingpig
    Member

    Shimano's tech docs for their low-end mechs reckon the axles of the jockey wheels should be vertically in line when on the biggest chainring and sprocket.
    Is the guide wheel of the rear mech perhaps not quite firm enough? Replacement set of jockey wheels with slightly shallower bushings?

    Posted 9 years ago #

  3. Kenny
    Member

    More description needed on "skippy". For example, does it always skip one direction, or either direction? Does it fully jump to the next cog, or just threaten to?

    Also, did you change your chain at the same time as your cassette? If not, that would be the first thing to do. If you replace your cassette with a new one and don't replace your chain at the same time, you're asking for trouble, in my experience.

    Posted 9 years ago #

  4. Uberuce
    Member

    It'll skip from one to another and back until I shift away from the troublesome cogs: 5 and 6, I think.

    New chain, yes.

    I read on t'interwebz (before buying this kit) that Tiagra and 105 ought to mesh just fine anyway, but the critical pairing is cassette to shifter. So I got a Tiagra cassette.

    Posted 9 years ago #

  5. Kenny
    Member

    Tiagra / 105 mix is fine, if they are both 10 speed. That's what I have - a 105 rear mech, a tiagra cassette, a 105 chain (or maybe it is a KMC one, meh), Tiagra STIs.

    If it skips from 5 to 6 and back, the one time I had something similar, my rear mech hanger was about to give out. When it did, I had quite a spectacular over the handlebars off, and nearly wrecked my wheel. So make sure that's ok.

    You say that barrel adjustment makes no difference? None whatsoever? You can't even make it slightly better, while making the rest less good at the same time? Could be a dud cassette, or alternatively you've not put the wheel in straight?

    Posted 9 years ago #

  6. algo
    Member

    @Uberuce - this is a long shot but it just happened to me (because I was in a hurry and I'm an eejit).. check the routing of the cable to the clamp on the rear derailleur - there's a notch where it must go - if it gets caught at any other point then the changing ratio is very slightly changed… also I'd check the integrity and the alignment of the dropout itself with the appropriate tool - the bike station has one you can borrow I think...

    Posted 9 years ago #

  7. wingpig
    Member

    Also, find your "B-tension adjustment screw" and twiddle it to get the guide wheel closer to the cassette, or perhaps further away if it's too close. Might make more difference to the middle sprockets as there's more choice where the chain can go from them.

    Alternatively, I had something similar once when my rear mech was fastened on too tight and wasn't springing back, resulting in too much tension in the chain and the chain trying to migrate drivesidewards.

    Posted 9 years ago #

  8. Cyclingmollie
    Member

    I've had that problem. I traced it to worn-out components. If it's not the chain, chainrings, mech or cassette then that just leaves the outer and inner gear cables. Check they are routed correctly first and if that doesn't work replace the outer and inner. I think an overlong chain would only cause problems in the lowest gears.

    Posted 9 years ago #

  9. Uberuce
    Member

    As I said/confessed, it's not been recabled in forever, and I fancy investigating those arthropod-looking compressionless cables Jagwire are doing for my brakes, so I'd be under the bar tape no matter what.

    Will undertake the aforementioned fiddles in the meantime, thanks, you lovely people.

    Posted 9 years ago #

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