Rear mech question - opinions needed

Discussion in 'UK and Europe' started by Oldskoolskater, Mar 16, 2004.

  1. My Deore LX mech is starting to not shift to smaller cogs
    (the smallest 4) very well, and I suspect the spring is too
    weak for the job as the mech has done 6000 miles. I
    currently get around the problem by shifting down two clicks
    and then back one! The rest of the mech looks fine, but I
    guess that I will not be able to get hold of just the spring
    for repair purposes? Should I get a new mech or try to get
    spares? I case you were wondering, the shifting cable has
    been replaced.

    Cheers

    Steve
     
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  2. Davep

    Davep Guest

    Oldskoolskater wrote:

    >My Deore LX mech is starting to not shift to smaller cogs
    >(the smallest 4) very well, and I suspect the spring is too
    >weak for the job as the mech has done 6000 miles. I
    >currently get around the problem by shifting down two
    >clicks and then back one! The rest of the mech looks fine,
    >but I guess that I will not be able to get hold of just the
    >spring for repair purposes? Should I get a new mech or try
    >to get spares? I case you were wondering, the shifting
    >cable has been replaced.
    >
    >Cheers
    >
    >Steve
    >
    >
    Have you removed the chain and checked the movement of
    the mech? Remove the cable , how does the mech feel when
    moved by hand?

    davep
     
  3. Anonymous

    Anonymous Guest

    Oldskoolskater posted ...

    > My Deore LX mech is starting to not shift to smaller cogs
    > (the smallest 4) very well, and I suspect the spring is
    > too weak for the job as the mech has done 6000 miles. I
    > currently get around the problem by shifting down two
    > clicks and then back one! The rest of the mech looks fine,
    > but I guess that I will not be able to get hold of just
    > the spring for repair purposes? Should I get a new mech or
    > try to get spares? I case you were wondering, the shifting
    > cable has been replaced.
    >
    > Cheers
    >
    > Steve

    I'd remove the chain and see that the mech gets full
    movement, and simply needs adjustment or maybe just a damn
    good clean and lubrication .. ;)

    I had a similar problem once where the cage of the rear mech
    had been hit while out riding and wasn't a parallelogram
    anymore, so wouldn't shift up to the higher gears at all ..
    it needed a replacement derailleur really, but a twist with
    a set of stillsons cured it for a year or so .. ;) If this
    is the case, make sure the chain return cogs are also
    running correctly and in-line with the chain run.

    Are you sure it's the rear mech and not the twist-grip or
    shifters that are causing the problem ? If the cable is new,
    as you say, be certain that it's been replaced, and works,
    correctly at both ends .. ;)

    --
    Paul

    (8(|) Homer rocks .. ;)
     
  4. Frank X

    Frank X Guest

    news:[email protected]...
    > Oldskoolskater posted ...
    >
    > > My Deore LX mech is starting to not shift to smaller
    > > cogs (the smallest 4) very well, and I suspect the
    > > spring is too weak for the job as the mech has done 6000
    > > miles. I currently get around the problem by shifting
    > > down two clicks and then back one! The rest of the mech
    > > looks fine, but I guess that I will not be able to get
    > > hold of just the spring for repair purposes? Should I
    > > get a new mech or try to get spares? I case you were
    > > wondering, the shifting cable has been replaced.
    > >
    > > Cheers
    > >
    > > Steve
    >
    > I'd remove the chain and see that the mech gets full
    > movement, and simply needs adjustment or maybe just a damn
    > good clean and lubrication .. ;)
    >
    > I had a similar problem once where the cage of the rear
    > mech had been hit while out riding and wasn't a
    > parallelogram anymore, so wouldn't shift up
    to
    > the higher gears at all .. it needed a replacement
    > derailleur really, but
    a
    > twist with a set of stillsons cured it for a year or
    > so .. ;)

    I've found that even the slightest knock to either my
    derailer or the replaceable dropout can cause it to shift
    badly. This tends to mean you can adjust it ok for
    particular sub ranges of gears but not for all 8 or 9 at the
    same time.

    I think the derailer cage is supposed to be vertical and
    that any deviation from this will cause a problem (but I
    could be wrong)
     
  5. Just Zis Guy

    Just Zis Guy Guest

    "Oldskoolskater" <[email protected]> wrote in message
    news:e41[email protected]...

    > My Deore LX mech is starting to not shift to smaller cogs
    > (the smallest 4) very well, and I suspect the spring is
    > too weak for the job as the mech has done 6000 miles.

    As has mine, with no problems. It's probably adjustment
    but could easily just be dirt in the pivots and stuff.
    I suggest:

    o Removing the mech from the bike and cleaning thoroughly o
    Ditto the chain and cassette o Refitting and lubricating
    with your lube of choice, especially the pivots on the
    parallelogram o Adjusting as per the service instructions at
    shimano.com, and o Trying again.

    For the ultimate in Smooth Shifting Performance [tm]
    fit a set of Tacx needle roller jockey wheels while
    you're about it.

    To be fair just adjusting, or lubing and adjusting would
    probably work, but it's Srping and the time of shining up
    the bikes is upon us (I cleaned and fettled mine on Sunday
    with excellent results).

    --
    Guy
    ===
    May contain traces of irony. Contents liable to settle after
    posting. http://www.chapmancentral.co.uk

    88% of helmet statistics are made up, 65% of them at
    Washington University
     
  6. > Remove the cable , how does the mech feel when moved
    > by hand?

    Feels quite stiff, but I'm not sure how much tension there
    should be? It may be significant, but I fitted a new chain
    recently and that obviously has much less sideways play than
    the worn one.

    Cheers

    Steve
     
  7. Dave Kahn

    Dave Kahn Guest

    [email protected] (Oldskoolskater) wrote in message news:<[email protected]>...
    > My Deore LX mech is starting to not shift to smaller cogs
    > (the smallest 4) very well, and I suspect the spring is
    > too weak for the job as the mech has done 6000 miles. I
    > currently get around the problem by shifting down two
    > clicks and then back one! The rest of the mech looks fine,
    > but I guess that I will not be able to get hold of just
    > the spring for repair purposes? Should I get a new mech or
    > try to get spares? I case you were wondering, the shifting
    > cable has been replaced.

    I'd be amazed if the spring had worn out that quickly.
    They should last for years and years. It's more likely to
    be something else causing too much resitance. I know you
    changed the cable, but if this was just the inner what
    condition is the outer in? Is the shifter stiff? Are the
    bearings in the mech itself stiff? If you take the mech
    completely off the bike and work it in your hands you'll
    have a good idea whether the spring is still strong and
    whether it moves freely. You will also be able to assess
    how easily the cable pulls when you operate the shifter
    by itself.

    --
    Dave...
     
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