Shimano LX B-Tension Adjustment: Need Heavier Spring?

Discussion in 'Cycling Equipment' started by HKEK, Oct 26, 2004.

  1. HKEK

    HKEK Guest

    The jockey pulley on my hardtail is riding against the 2 largest cogs.
    It appears that there is insufficient spring tension even with the
    B-screw adjusted fully in. The chain length seems right and there is
    little force on the derailleur from the cable (it is the very flexible
    IRD metawire).

    After reading a number of posts to this group, I tried some of the
    suggestions including a longer screw. None seemed to help. Manually
    rotating the derailleur indicates that there is more than ample range
    of motion available; however, it appears that the spring is simply too
    weak.

    Is the spring replaceable and is there a spring available that has a
    higher spring rate? Is it possible to remove the spring and re-install
    it with an extra turn or two to increase the preload?

    The derailleur is a Shimano LX special edition that was only avaible
    in a black and gold finish. The cassette is an XT with a 34 tooth cog.

    Thanks in advance for your help.
     
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  2. Richard Tack

    Richard Tack Guest

    HKEK wrote:

    > The jockey pulley on my hardtail is riding against the 2 largest cogs.
    > It appears that there is insufficient spring tension even with the
    > B-screw adjusted fully in. The chain length seems right and there is
    > little force on the derailleur from the cable (it is the very flexible
    > IRD metawire).
    >
    > After reading a number of posts to this group, I tried some of the
    > suggestions including a longer screw. None seemed to help. Manually
    > rotating the derailleur indicates that there is more than ample range
    > of motion available; however, it appears that the spring is simply too
    > weak.
    >
    > Is the spring replaceable and is there a spring available that has a
    > higher spring rate? Is it possible to remove the spring and re-install
    > it with an extra turn or two to increase the preload?
    >
    > The derailleur is a Shimano LX special edition that was only avaible
    > in a black and gold finish. The cassette is an XT with a 34 tooth cog.
    >
    > Thanks in advance for your help.


    Sounds like the der cage is not long enough or the chain is
    too long.
     
  3. HKEK

    HKEK Guest

    Might be. I know the XT is available in different lengths, I can't say
    the same for the LX. Perhaps I should just upgrade.
     
  4. HKEK

    HKEK Guest

    Shimano claims that the LX derailleur is compatible with a 34 tooth cassette!
     
  5. dianne_1234

    dianne_1234 Guest

    On 26 Oct 2004 17:30:57 -0700, [email protected] (HKEK) wrote:

    >The jockey pulley on my hardtail is riding against the 2 largest cogs.
    >It appears that there is insufficient spring tension even with the
    >B-screw adjusted fully in. The chain length seems right and there is
    >little force on the derailleur from the cable (it is the very flexible
    >IRD metawire).
    >
    >After reading a number of posts to this group, I tried some of the
    >suggestions including a longer screw. None seemed to help. Manually
    >rotating the derailleur indicates that there is more than ample range
    >of motion available; however, it appears that the spring is simply too
    >weak.
    >
    >Is the spring replaceable and is there a spring available that has a
    >higher spring rate? Is it possible to remove the spring and re-install
    >it with an extra turn or two to increase the preload?
    >
    >The derailleur is a Shimano LX special edition that was only avaible
    >in a black and gold finish. The cassette is an XT with a 34 tooth cog.
    >
    >Thanks in advance for your help.


    I've solved a similar problem (on an old 105 rear derailleur) by
    reducing the A-tension.

    In this exploded view,
    http://www.shimano-europe.com/cycling/phpimages/product/exp_view/RD_M570.pdf
    I installed the spring (number 10 in the image) and installed it in a
    different hole in the cage (number 11).
     
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