Shimano cantilever BR-M732 asymmetry

Discussion in 'Cycling Equipment' started by Nicholas Grieco, Jan 8, 2005.

  1. Last weekend, I installed Shimano cantilever brake BR-M732, which is
    sometimes called 'XT2', or 'XT-II" as I understand it.

    I found that the arm with secondary spring tension adjustment has more drag
    at the pivot than the other arm. This causes the two arms to respond
    asymmetrically when the brake cable is pulled or released.

    The drag appears to be integral to that cantilever arm; different greases
    and lubes on the brake bosses did not correct for the differential.
    Loosening or tightening the pivot bolt had no affect. Unequal left/right
    spring tension and/or straddle cable length do not directly address this
    problem.

    With some Googling, I found a post referring to this issue:
    http://tinyurl.com/6273n, or
    http://groups.google.co.uk/groups?hl=en&lr=&[email protected].
    edu

    Has anybody else here experienced this? Did Shimano make a running change
    to the 732 to correct the issue? Does the 730 have the same problem?

    Thanks,
    Nicholas
     
    Tags:


  2. Nicholas Grieco wrote:

    > Last weekend, I installed Shimano cantilever brake BR-M732, which is
    > sometimes called 'XT2', or 'XT-II" as I understand it.
    >
    > I found that the arm with secondary spring tension adjustment has more drag
    > at the pivot than the other arm. This causes the two arms to respond
    > asymmetrically when the brake cable is pulled or released.
    >
    > The drag appears to be integral to that cantilever arm; different greases
    > and lubes on the brake bosses did not correct for the differential.
    > Loosening or tightening the pivot bolt had no affect. Unequal left/right
    > spring tension and/or straddle cable length do not directly address this
    > problem.


    > Has anybody else here experienced this? Did Shimano make a running change
    > to the 732 to correct the issue? Does the 730 have the same problem?


    This is not likely a flaw in the cantis, more likely a flaw in the frame
    studs. Sometimes they can get bulged out near the open end from
    overtightening of the bolts, sometimes they're imperfect in other ways.
    This can often be corrected by careful use of emery paper or a file.

    Also, those cantis have a two-position spring setting (on each side.)

    One of the positions is labeled "SLR." This is the lower-tension
    setting, for use with brake levers that incorporate their own return
    springs.

    The other, stiffer setting is for older brake levers that relied on the
    canti springs alone.

    I have a detailed series of Web pages on this, but now that I look, it
    appears that I neglected to place a link to them anywhere on my site.

    See:
    http://sheldonbrown.com/harris/cantilevers/pages/cantilevers-xt2-02.html

    Sheldon "Oopps!" Brown
    +----------------------------------------------------+
    | The two most common elements in the Universe are |
    | hydrogen and stupidity. --Harlan Ellison |
    +----------------------------------------------------+
    Harris Cyclery, West Newton, Massachusetts
    Phone 617-244-9772 FAX 617-244-1041
    http://harriscyclery.com
    Hard-to-find parts shipped Worldwide
    http://captainbike.com http://sheldonbrown.com
     
Loading...
Loading...