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Jockey wheels

always_tyredalways_tyred Posts: 4,965
edited December 2009 in The workshop
Okay - replaced 10sp cassette with identical 10sp cassette, replace Sram chain with identical Sram chain.

Now, when in a low gear (21, 23 and 25) and the small ring (34T) the chain is riding around the lowermost jockey wheel, causing the rear mech and chain to buck and the gears to skip.

I replaced the jockey wheel in case it was sticking, but its doing the same thing.

Not a seized chain link. Chain line identical to previously, and works okay in the big ring, even though this crosses the chain.

I shortened the chain as much as I dare.

Any ideas what the problem is? I'm stumped.

Posts

  • cjcpcjcp Posts: 13,345
    Have you tightened up the cassette completely? (Although I remember you saying last year that you were paranoid about this, when something similar happened to me.)
    FCN 2-4.

    "What happens when the hammer goes down, kids?"
    "It stays down, Daddy."
    "Exactly."
  • cjcp wrote:
    Have you tightened up the cassette completely? (Although I remember you saying last year that you were paranoid about this, when something similar happened to me.)
    Yup. Took it off and put is back on again last night.
  • cjcpcjcp Posts: 13,345
    All the spacers in?

    Is th bottom of the rear mech (where the chain exits) bent a little?
    FCN 2-4.

    "What happens when the hammer goes down, kids?"
    "It stays down, Daddy."
    "Exactly."
  • None of the above. The kit is all fairly new and was running smoothly enough (other than being filthy) prior to the chain/cassette replacement.

    And, remember, it works fine in the big ring.

    There is a finite possibility that both the old and the replacement (which was not new) jockey wheels are a bit stiff, such that the lower chain tension in the small ring causes problems to manifest, but I tested the damn replacement for exactly this.

    I don't want to fork out for replacement jockey wheels that do the exact same thing, but I forsee it in my future....
  • gabriel959gabriel959 Posts: 4,227
    Ask in the workshop of the road section - you will get an answer.
    x-x-x-x-x-x-x-x
    Commuting / Winter rides - Jamis Renegade Expert
    Pootling / Offroad - All-City Macho Man Disc
    Fast rides Cannondale SuperSix Ultegra
  • gabriel959 wrote:
    Ask in the workshop of the road section - you will get an answer.
    As suggested - I've reposted in the scary roadie board. :shock:
  • cjcpcjcp Posts: 13,345
    If there's an issue with the rear mech, I'm going to do a little dance. :D

    Actually, the reason I suggested that was that I had a little clicking from the rear mech in the same gears you mentioned, and I think it's because the rear mech is bent in some very small way, almost as if it's bent that little metal thingy/guard at the bottom of the mech. I haven't got round to properly checking it.

    Also, don't jockey wheels rotate (and so have to be fitted) a certain way?
    FCN 2-4.

    "What happens when the hammer goes down, kids?"
    "It stays down, Daddy."
    "Exactly."
  • gs3gs3 Posts: 249
    Is the chain you put on exactly the same number of links as the one you took off or is it longer??

    Just thought I'd ask.

    .
  • Well, I think it was a bad SRAM chain - it was the cheapest 10sp they do - that didn't have enough flex to navigate the jockey wheel. It would probably have "worn in" over time, but it was taking a lot of material off the jockey wheel in the mean time.

    I replaced the (new) SRAM chain with a shim 105 and it worked a hell of a lot better. I delved into my box of misc parts and installed my final jockey wheel and now its fine. The original still didn't work, so I guess that was more worn than I thought. A brand new one might have had deep enough teeth to catch the chain links - but I maintain that the stiff chain was going to cause excessive wear. That's three SRAM chains i've had issues with this year - I had one of the ones that was recalled that was a bit "clicky" although I couldn't be arsed to give it back - I had a link freeze on a brand new one after 3 days - and now this. Shame - they used to be better than Shimano chains.

    I have to say, I'm quite suprised how sensitive the 10 speed is - I've used jockey wheels so worn they look like snowflakes with no problem on 8/9 speed before now.
  • VegeetaVegeeta Posts: 6,411
    Adjust the B tension so that when the mech is in the position of easiest gear you can put a biro pen between the jockey wheel and the cassette.
    Rule 64:

    Cornering confidence generally increases with time and experience. This pattern continues until it falls sharply and suddenly.

    http://www.velominati.com/blog/the-rules/
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