Seatpost Clamp Sizing

Discussion in 'Cycling Equipment' started by D'ohBoy, Nov 22, 2005.

  1. D'ohBoy

    D'ohBoy Guest

    Greetings!

    I have stripped the threads on my seatpost clamp and went to an lbs to
    find a new one (seatpost = 27.2). The clamp sold to me wouldn't fit
    around the seatpost due to the machined ridge at the top that prevents
    sliding down the seat tube. I probably could have gotten it on the
    seat tube (the clamp was slightly out of round and would have required
    some wanking) but I couldn't have gotten the seatpost in it.

    The frame is columbus foco and seems very thin at the clamp area. Does
    anyone know what size clamp would be appropriate (if the tubing were
    0.4 mm at that point, I would suspect a ~28.0 mm clamp would be
    appropriate).

    The ridge on the old clamp appears to have been ground off. Maybe do
    that with the clamp that will fit the seattube?

    TIA and Happy Thanksgiving!

    App
     
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  2. jtaylor

    jtaylor Guest

    "D'ohBoy" <[email protected]> wrote in message
    news:[email protected]
    > Greetings!
    >
    > I have stripped the threads on my seatpost clamp and went to an lbs to
    > find a new one (seatpost = 27.2). The clamp sold to me wouldn't fit
    > around the seatpost due to the machined ridge at the top that prevents
    > sliding down the seat tube. I probably could have gotten it on the
    > seat tube (the clamp was slightly out of round and would have required
    > some wanking) but I couldn't have gotten the seatpost in it.
    >


    File it.

    And don't worry if alarmists tell you this will cause fatigue failure from
    the scratches the file leaves...
     
  3. D'ohBoy wrote:
    > Greetings!
    >
    > I have stripped the threads on my seatpost clamp and went to an lbs to
    > find a new one (seatpost = 27.2). The clamp sold to me wouldn't fit
    > around the seatpost due to the machined ridge at the top that prevents
    > sliding down the seat tube. I probably could have gotten it on the
    > seat tube (the clamp was slightly out of round and would have required
    > some wanking) but I couldn't have gotten the seatpost in it.
    >
    > The frame is columbus foco and seems very thin at the clamp area. Does
    > anyone know what size clamp would be appropriate (if the tubing were
    > 0.4 mm at that point, I would suspect a ~28.0 mm clamp would be
    > appropriate).
    >
    > The ridge on the old clamp appears to have been ground off. Maybe do
    > that with the clamp that will fit the seattube?
    >
    > TIA and Happy Thanksgiving!
    >
    > App


    I assume you mean your frame has the external seattube clamp like the
    ones pictured in the link below.

    http://www.nashbar.com/profile.cfm?...rand=&sku=2296&storetype=&estoreid=&pagename=

    They only come in three sizes. 1 1/8, 1 1/4, 1 3/8. Or the metric
    equivalent of 28.6, 31.8, 34.9. Get out your vernier calipers and put
    them at the top of the seattube and determine the outside diameter of
    the top of the seattube. These clamps have a ridge on the inside, a
    lip, to prevent the clamp from sliding down the seattube. The lip will
    be on top of the seattube.
     
  4. D'ohBoy

    D'ohBoy Guest

    Quoth JT:

    > File it.


    Yah, I could do that and did think of it but I would rather not have to
    do that if possible. Settled on a Salsa LipLock with a barrel nut and
    that will accommodate my odd OD without damaging the threads of the
    clamp via the oblique bolt angle relative to the threads.

    Thanks again for all of y'all's input.

    D'ohBoy
     
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