Rear mech driving me nuts

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Comments

  • Jamey
    Jamey Posts: 2,152
    Just done some calculating (I knew there was a good reason to keep the log) and the bike has done 1,179 miles since the cables were last changed.

    Do you think this is a fair length of time for unsealed cable to last in the British winter (October to January)?
  • alfablue
    alfablue Posts: 8,497
    I think unsealed cables could easily deteriorate in that time if riding in foul weather (a few weeks could do it), though I would not bet on this as being the issue given that you found the existing one to be running smoothly. Worth a try though.
  • Maybe a worn chain and/or stiff link(s)? Cable bends too tight (at the front too)? STI lever problem? Cable routing under bottom bracket, does it feed through the little plastic guide correctly? too much play in top jockey wheel on the mech?
    <a>road</a>
  • Jamey
    Jamey Posts: 2,152
    The chain hasn't got to 0.75 on the chain checker tool yet so it's ok, and no stiff links. The routing under the BB is fine too.

    The cable bend (rear loop) is a possible cause I still need to eliminate and the top jockey wheel is something I haven't checked yet so I'll do that, thanks.

    Think the STis are fine. Certainly seem to be working properly.
  • alfablue
    alfablue Posts: 8,497
    The top jockey wheel (guide pulley) is designed to have some lateral play, it is essential to smooth meshing (and accommodate inevitable minor inaccuracies with indexing).
  • Jamey
    Jamey Posts: 2,152
    How much is too much, then?
  • alfablue
    alfablue Posts: 8,497
    I have read that there should be between 1mm and 2mm play. It would be extremely unlikely for this to be the issue unless the mech was actually faulty.
  • Jamey
    Jamey Posts: 2,152
    Yeah, I know, I'm just at the end of my tether and willing to try anything. Honestly, if the new cable doesn't fix it I'm going to cry. Thanks for all your help though, I do appreciate it.
  • alfablue
    alfablue Posts: 8,497
    Be strong, Jamey!
  • Jamey
    Jamey Posts: 2,152
    :)

    Once (if) this all gets sorted I'll probably be switching to sealed cables though, so that's one good thing to come out of this I guess.
  • Jamey
    Jamey Posts: 2,152
    Well I'm now the proud owner of some Park Cable Cutters, a gear inner wire, four cable stop thingys and 1.5m of outer/housing (wanted extra to play with). Should hopefully get time to fit it Sunday so wish me luck.
  • Jamey
    Jamey Posts: 2,152
    Update - just fitted the new cable and it's cured the problem. Once it was on I had the mech adjusted and working in five minutes flat so I guess I didn't do a very good job of cleaning the old bit of cable when I tested that.

    Birthday next month so sealed cables will be on my list. Are the Gore RideOn ones noticeably better than the Transfil Mudlovers? Is it worth the extra (bearing in mind it'll be a birthday pressie :) )?
  • alfablue
    alfablue Posts: 8,497
    Hey, Jamey! Glad that sorted it (and that it was the issue I predicted 8) ).

    As for the cables, I have never used the Gore ones, for me the Mudlovers have worked fine so I wouldn't spend any more, but if its a pressie...well, perhaps I would go for the Gore - I think they are well liked (though whether they are actually any better, I don't know). Are you intending getting brake and gear cables? I think brake cables are less essential, but maybe as its a pressie, you could get brake and gear Mudlovers for the price of Gear only Gore.
  • Jamey
    Jamey Posts: 2,152
    Hmmm... Yeah.

    As you say, brake cables are less required but I'm a bit fussy and would like to have the same brand/model for all four cables. A bit like on my car - I hate having different tyres on different wheels, even though it probably doesn't make much difference.
  • alfablue
    alfablue Posts: 8,497
    I like the cut of your jib - I would have them all matching too (mild case of OCD here!) :wink:
  • Jamey
    Jamey Posts: 2,152
    Healthy case, I'd say ;)
  • Jamey
    Jamey Posts: 2,152
    Oh, alfa (or anyone else that knows), one more quick question about sealed cables.

    When you're fitting a new sealed cable and you get to the end of the routing do you have to scrape off the seal from the inner wire before you attach it to the pinch bolt? If so, how do you remove it? Does one of those holes in the middle of the Park Cable Cutters do the job? I don't own any cable strippers and would rather not have to buy a set if I can avoid it.
  • alfablue
    alfablue Posts: 8,497
    You only need to have the smallest bit of bare cable, just so nothing fouls the lining. A craft knife is all you need, run it round gently and pull off the excess. No scraping required, it just slides off. It isn't firmly stuck to the cable (like an electrical cable) it is designed to be very low friction.
  • Jamey
    Jamey Posts: 2,152
    Cool, thank you.
  • Jamey
    Jamey Posts: 2,152
    Another question for anyone still following this thread :)

    I now have a Rollamajig (thank you kind forum member) and was wondering which of these options is likely to be the most reliable and long-lasting combo:
    • Rollamajig plus normal cables.
    • Rollamajig plus sealed cables.
    • Sealed cables without Rollamajig.

    Whaddya reckon?
  • sealed cables and rollamajig.

    Sealed stops the crud getting in, the rollamajig will reduce the loop at the back meaning you're less likely to snag it on undergrowth.
  • Jamey
    Jamey Posts: 2,152
    Cool. That's what I was thinking :) I like the best and braces approach.
  • Jamey
    Jamey Posts: 2,152
    Hmmm... Having now read a lot of reviews of Rollamajigs I'm thinking I might go for just the sealed cables on their own.

    Reason being the Rollamajig will expose a lot of inner cable at the back which is likely to allow dirt in (isn't it?), which defeats the point of sealed cables.
  • whyamihere
    whyamihere Posts: 7,716
    No more than is exposed anyway between the end of the cable run and the clamping bolt. I never had a problem with the Rollamajig.
  • Jamey
    Jamey Posts: 2,152
    But with the Rollamajig you've got the bit you mention (from rear mech entrance to pinch bolt) and then the exposed length of inner that runs around the wheel of the Rollamajig as well.

    Maybe it doesn't make a difference, it just strikes me that a Rollamajig is designed to make cables work well even when they're a bit dirty whereas sealed cables stop the dirt full-stop, so having them both might be unnecessary at best, and more things to go wrong at worst.

    A fair few of the reviews also said that the Rollamajig just made it feel like there were always new cables on the bike, rather than actually being better than new cables. So if they only come into their own once dirt begins to creep in, and sealed cables stop dirt creeping in then the 'jig will never actually get a chance to do its job properly.

    That was my thinking, happy to be convinced otherwise :)
  • whyamihere
    whyamihere Posts: 7,716
    The only problem is that fully sealed cables aren't impregnable. Dirt can and will still get in, just not as much as normal.
  • Jamey
    Jamey Posts: 2,152
    So maybe the question is whether it's better to have the end of the sealed liner pointing forward (as with a normal setup) but with a shorter length of exposed inner or whether to have it pointing backward (as with a Rollamajig) but have a slightly longer length of exposed inner.

    What do you think?