seatpost close but not quite...OK?

Discussion in 'Cycling Equipment' started by dookie, Sep 21, 2006.

  1. dookie

    dookie Guest

    26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    it's an absolute jewel of a post (custom ti, by torque products in kent,
    oh).

    opinions?
     
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  2. Kinky Cowboy

    Kinky Cowboy Guest

    On Fri, 22 Sep 2006 00:13:18 GMT, "dookie"
    <[email protected]~obvious~dooksucks.com> wrote:

    >26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    >it's an absolute jewel of a post (custom ti, by torque products in kent,
    >oh).
    >
    >opinions?
    >


    Get a piece of 0.1mm shim stock. I put a 26.4 post in a 26.8 hole
    using 0.2mm shim stock wrapped around it and it's been fine for the
    last 20 years. Some people might think I haven't completed long term
    testing yet, but so far so good.

    Kinky Cowboy*

    *Batteries not included
    May contain traces of nuts
    Your milage may vary
     
  3. Kenny

    Kenny Guest

    dookie wrote:
    > 26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    > it's an absolute jewel of a post (custom ti, by torque products in kent,
    > oh).
    >
    > opinions?


    You will need to use a shim.
     
  4. dookie wrote:
    > 26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    > it's an absolute jewel of a post (custom ti, by torque products in kent,
    > oh).
    >
    > opinions?


    Tried it yet? Don't let it fall in and get scratched if it turns out to
    be loose. --D-y
     
  5. Mark Hickey

    Mark Hickey Guest

    "dookie" <[email protected]~obvious~dooksucks.com> wrote:

    >26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    >it's an absolute jewel of a post (custom ti, by torque products in kent,
    >oh).
    >
    >opinions?


    Bad idea. 0.2mm seems like almost nothing, but trying to compress the
    diameter of that seat tube clamp an extra 0.2mm beyond its designed
    limits takes a LOT of torque. You will likely end up with a slipping
    seat post AND perhaps damage your frame's seat post clamp at the same
    time.

    Mark Hickey
    Habanero Cycles
    http://www.habcycles.com
    Home of the $795 ti frame
     
  6. Artoi

    Artoi Guest

    In article <[email protected]>,
    Kinky Cowboy <[email protected]> wrote:

    > On Fri, 22 Sep 2006 00:13:18 GMT, "dookie"
    > <[email protected]~obvious~dooksucks.com> wrote:
    >
    > >26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    > >it's an absolute jewel of a post (custom ti, by torque products in kent,
    > >oh).
    > >
    > >opinions?
    > >

    >
    > Get a piece of 0.1mm shim stock. I put a 26.4 post in a 26.8 hole
    > using 0.2mm shim stock wrapped around it and it's been fine for the
    > last 20 years. Some people might think I haven't completed long term
    > testing yet, but so far so good.


    Should one consider the effect of different metal on possible corrosion
    or other interactive effects here?
    --
     
  7. Mark Hickey wrote:

    > Bad idea. 0.2mm seems like almost nothing, but trying to compress the
    > diameter of that seat tube clamp an extra 0.2mm beyond its designed
    > limits takes a LOT of torque. You will likely end up with a slipping
    > seat post AND perhaps damage your frame's seat post clamp at the same
    > time.


    .... or find yourself with a broken binder, and an unattached post, in
    the middle of a ride.
    Get yourself a piece of mylar to use as a shim. It does not need to be
    as thick as the difference in radii; a bit thicker is better, in fact.
    Cut it into a trapezoid, insert it upside down as a wedge as far as it
    can go. Trim off whatever is left sticking out.
    That will prevent corrosion, too.

    Sergio
    Pisa
     
  8. dookie wrote:
    > 26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    > it's an absolute jewel of a post (custom ti, by torque products in kent,
    > oh).
    >
    > opinions? Shim it,cut from a coke or pepsi can.
     
  9. Donga

    Donga Guest

    dookie wrote:
    > 26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    > it's an absolute jewel of a post (custom ti, by torque products in kent,
    > oh).
    >
    > opinions?


    I've got an undersized Ti post in an old Litespeed Ultimate frame. The
    post is shimmed with a piece of metal that may well be cut out of a
    coke can. It works fine. I've also used coke can to shim a handlebar in
    a stem.

    Donga
     
  10. jmoryl

    jmoryl New Member

    Joined:
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    Yes, make a shim. I've got an ITM Millenium 29.6 mm post that is being used on a frame that takes a 30.0 mm post with a 0.008" brass shim. A well equipped hobby shop has thin sheet metal in various thicknesses.
     
  11. Kinky Cowboy

    Kinky Cowboy Guest

    On Fri, 22 Sep 2006 06:28:53 GMT, Artoi <[email protected]> wrote:

    >In article <[email protected]>,
    > Kinky Cowboy <[email protected]> wrote:
    >
    >> On Fri, 22 Sep 2006 00:13:18 GMT, "dookie"
    >> <[email protected]~obvious~dooksucks.com> wrote:
    >>
    >> >26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    >> >it's an absolute jewel of a post (custom ti, by torque products in kent,
    >> >oh).
    >> >
    >> >opinions?
    >> >

    >>
    >> Get a piece of 0.1mm shim stock. I put a 26.4 post in a 26.8 hole
    >> using 0.2mm shim stock wrapped around it and it's been fine for the
    >> last 20 years. Some people might think I haven't completed long term
    >> testing yet, but so far so good.

    >
    >Should one consider the effect of different metal on possible corrosion
    >or other interactive effects here?


    One should consider it, then dismiss it provided one keeps the thing
    clean, dry and greased with Copaslip or similar. Mine is a steel post
    (nickel plated CroMo) with a nickel plated steel shim in a CroMo
    frame, so I'm not too worried.

    A 27.0mm hole sounds like it's going to be a steel frame, and I had a
    titanium post in a steel frame for 15 years without taking it out
    once, and it popped out clean as a whistle when I dismantled the bike.

    Kinky Cowboy*

    *Batteries not included
    May contain traces of nuts
    Your milage may vary
     
  12. Werehatrack

    Werehatrack Guest

    On Fri, 22 Sep 2006 00:13:18 GMT, "dookie"
    <[email protected]~obvious~dooksucks.com> wrote:

    >26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try it.
    >it's an absolute jewel of a post (custom ti, by torque products in kent,
    >oh).
    >
    >opinions?


    0.2mm may not seem like much, but this is an area where a precision
    fit is a good and necessary thing. There's a reason why seat posts
    are supplied in so many diameters; it's because a precision fit is
    more than just a cosmetic issue.

    OTOH, with a shim of a suitable length, in a steel frame, it might
    work just fine.

    I personally wouldn't do it, however, for a variety of reasons.
    --
    Typoes are a feature, not a bug.
    Some gardening required to reply via email.
    Words processed in a facility that contains nuts.
     
  13. Andrew Price

    Andrew Price Guest

    On Mon, 25 Sep 2006 17:49:08 GMT, Werehatrack
    <[email protected]> wrote:

    >0.2mm may not seem like much, but this is an area where a precision
    >fit is a good and necessary thing. There's a reason why seat posts
    >are supplied in so many diameters; it's because a precision fit is
    >more than just a cosmetic issue.


    I fully agree - from the bitter experience of a seatpost supplied with
    a new bicycle (surprisingly, from a very reputable German
    manufacturer), which was 0.1 mm less than its nominal diameter. I had
    to tighten the clamp to the point of bursting, otherwise the post
    gradually slid down over a distance of 20km or so.

    I eventually replaced the post, but before that, it was the annoyance
    of constant adjustment, with the fear that I'd push the clamp beyond
    the point of no return.
     
  14. dookie

    dookie Guest

    so, i took your advice...

    the frame is ti, so it's nice and flexible. i'd ridden the post as-was for
    ~100mi offroad without issue. nonetheless, i removed it, went to the hobby
    shop and picked up some brass shim stock (0.1mm is ~0.004", i got 0.005"
    stock), greased both sides, wrapped it around the post and reinstalled. the
    shim is nearly as long as the post is deep and it's quite snug now.
    amazingly, the shim adheres to the frame better than the post, so i was able
    to push it down flush and insert the post without it moving. excellent!

    thanks much.

    "dookie" <[email protected]~obvious~dooksucks.com> wrote in message
    news:[email protected]
    > 26.8mm post in a 27.0 frame? seems awfully close and i'm tempted to try
    > it. it's an absolute jewel of a post (custom ti, by torque products in
    > kent, oh).
    >
    > opinions?
    >
     
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