Seat post is 25 and tube 27,2

Discussion in 'Cycling Equipment' started by Gv, Feb 19, 2003.

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  1. Gv

    Gv Guest

    Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    installed the shim but the gap between the shim and the post is still too big: when I fasten the
    seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving this
    problem? I've thought of cutting an inner tube to the length of the seatpost that is inserted in the
    seat tube and slidding the seat tube in it, this way the seatpost will be a bit bigger in diameter
    and the plastic of the inner tube material will distribute preassure evenly. What do you think?
    Regards, Gonzalo
     
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  2. Peter Cole

    Peter Cole Guest

    "GV" <[email protected]> wrote in message
    news:[email protected]...
    > Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    > installed the shim but the gap between the shim and the post is still too big: when I fasten the
    > seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving
    > this problem? I've thought of cutting an inner tube to the length of the seatpost that is inserted
    > in the seat tube and slidding the seat tube in it, this way the seatpost will be a bit bigger in
    > diameter and the plastic of the inner tube material will distribute preassure evenly.

    An inner tube probably won't work because the rubber is too compressible. Hard plastic sheet will
    work, as will thin metal sheet. I've made shims from aluminum soft drink cans and aluminum roof
    flashing material.
     
  3. On Wed, 19 Feb 2003 06:16:13 -0500, GV wrote:

    > Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    > installed the shim but the gap between the shim and the post is still too big: when I fasten the
    > seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving
    > this problem?

    Get a post that fits. There are millions of 27.2 seatposts available.

    --

    David L. Johnson

    __o | Accept risk. Accept responsibility. Put a lawyer out of _`\(,_ | business. (_)/ (_) |
     
  4. Appkiller

    Appkiller Guest

    Don't screw around with this. Get the right shim from USE.

    App

    [email protected] (GV) wrote in message
    news:<[email protected]>...
    > Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    > installed the shim but the gap between the shim and the post is still too big: when I fasten the
    > seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving
    > this problem? I've thought of cutting an inner tube to the length of the seatpost that is inserted
    > in the seat tube and slidding the seat tube in it, this way the seatpost will be a bit bigger in
    > diameter and the plastic of the inner tube material will distribute preassure evenly. What do you
    > think? Regards, Gonzalo
     
  5. In article <[email protected]>, GV
    <[email protected]> wrote:
    >Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    >installed the shim but the gap between the shim and the post is still too big: when I fasten the
    >seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving
    >this problem?

    If you bought it new, and your bike really is 27.2, then you have the wrong shim.

    > I've thought of cutting an inner tube to the length of the seatpost that is inserted in the seat
    > tube and slidding the seat tube in it, this way the seatpost will be a bit bigger in diameter and
    > the plastic of the inner tube material will distribute preassure evenly.

    No you need to use some kind of hard material like a beer can. Rubber is not going to cut it.

    --Paul
     
  6. Tdwfl

    Tdwfl Guest

    > "David L. Johnson" DavidL. Johnson wrote: >Get a post that fits. There are
    millions of 27.2 seatposts available.

    I believe that the intended way to use that post is with a shim. He probably just has the
    wrong shim.

    tim
     
  7. A Muzi

    A Muzi Guest

    > > "David L. Johnson" DavidL. Johnson wrote: >Get a post that fits. There
    are
    > millions of 27.2 seatposts available.

    "TDWFL" <[email protected]> wrote in message news:[email protected]...
    > I believe that the intended way to use that post is with a shim. He
    probably
    > just has the wrong shim.

    I agree. There are several systems built around 25.0 seatposts and others based on 25.4 material.
    You cannot directly swap the shims as this gentleman discovered ( a 25.4=>27.2 shim isn't useful in
    a 25.0=>27.2 application). Some of these systemes (USE for example) are well-designed and well made.
    Others are tacky and sloppy.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  8. Bluto

    Bluto Guest

    [email protected] (GV) wrote:

    > Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    > installed the shim but the gap between the shim and the post is still too big: when I fasten the
    > seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving
    > this problem?

    Your shim is the wrong size. It could be intended for a frame bore less than 27.2mm, or it might be
    for a post larger than 25.0mm. Or else your frame needs a fatter post than 27.2mm.

    Get the right size shim and your problem will be solved. But why didn't you just get the right size
    post for your frame?

    Chalo Colina
     
  9. Pete Biggs

    Pete Biggs Guest

    TDWFL wrote:

    >> Get a post that fits. There are millions of 27.2 seatposts available.
    >
    > I believe that the intended way to use that post is with a shim. He probably just has the
    > wrong shim.

    That's right (and USE do make 27.2 shims - I have one), although USE also make 27.2 versions of
    their seatposts as well as 25.0. But of course, a
    27.2 post should be no better if the both are actually 27.2.

    However, I suspect USE shims are slightly under diameter, and the particularly slippery anodised
    finish doesn't help. The three different-size USE shims I've used with three different bikes have
    only just been a tight enough fit. I can imagine that they might slip in certain frames.

    Using a different binder (or modifying if built-in type) might help, as might simply greasing the
    bolt. If this failed, I would consider a different 27.2 seatpost. They are not all the same, really.

    ~PB
     
  10. Pete Biggs

    Pete Biggs Guest

    Pete Biggs wrote:
    > However, I suspect USE shims are slightly under diameter, and the particularly slippery anodised
    > finish doesn't help. The three different-size USE shims I've used with three different bikes have
    > only just been a tight enough fit. I can imagine that they might slip in certain frames.

    or that the post inside it would slip

    ~PB
     
  11. Gv

    Gv Guest

    The use carbon post is only made in 25mm you have to use shims to adapt it to other diameters. I
    thought that the shim was for 27,2mm tubes...I gave for sure something that was not correct. I will
    get a 27,2 shim or use a hard plastic sleeve. Thanks to all, Gonzalo

    [email protected] (Bluto) wrote in message
    news:<[email protected]>...
    > [email protected] (GV) wrote:
    >
    > > Hi, I've purchased an use alien 25mm seatpost, it came with a shim for 27,2 seat tubes. I've
    > > installed the shim but the gap between the shim and the post is still too big: when I fasten the
    > > seat post bolt, the seatpost can still be moved up and down.....what do you suggest for solving
    > > this problem?
    >
    > Your shim is the wrong size. It could be intended for a frame bore less than 27.2mm, or it might
    > be for a post larger than 25.0mm. Or else your frame needs a fatter post than 27.2mm.
    >
    > Get the right size shim and your problem will be solved. But why didn't you just get the right
    > size post for your frame?
    >
    > Chalo Colina
     
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