Shortening a seat tube

Discussion in 'Cycling Equipment' started by Robert Strickla, Feb 17, 2003.

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  1. I've got a frame I'm about to get repainted but I was wondering if there would be any reason why I
    shouldn't have the seat tube 'adjusted' at the same time. The problem is that there is a good 4 cm
    of seat tube above the top tube. This means that to get a good fistful of seat post to protrude
    above the seat tube, the saddle ends up being a cm or two higher than it needs to be. This would be
    no big deal except that I think I would be a lot more comfortable sitting a cm or two lower as well
    as being a little closer to the bars. Are there any structural reasons why I couldn't just have a
    frame builder take 2 cm off the tube before I get it repainted?

    Thanks in advance, Rob Strickland
     
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  2. In article <[email protected]>, Robert Strickland
    <[email protected]> wrote:
    >I've got a frame I'm about to get repainted but I was wondering if there would be any reason why I
    >shouldn't have the seat tube 'adjusted' at the same time. The problem is that there is a good 4 cm
    >of seat tube above the top tube. This means that to get a good fistful of seat post to protrude
    >above the seat tube, the saddle ends up being a cm or two higher than it needs to be. This would be
    >no big deal except that I think I would be a lot more comfortable sitting a cm or two lower as well
    >as being a little closer to the bars. Are there any structural reasons why I couldn't just have a
    >frame builder take 2 cm off the tube before I get it repainted?

    Assuming the bike is out of warranty and a qualified person does the work, there is no problem
    with doing this. They can shorten the seat tube, cut a slot in it, and you can use an aluminum
    clamp to fix the seatpost in place. Some bikes come that way from the manufacturer, it is
    sometimes done as a cost-saving measure since a TIG-welded bike can be produced more cheaply
    without the integrated binder.

    --Paul
     
  3. "Robert Strickland" <[email protected]> wrote in message
    news:[email protected]...
    > I've got a frame I'm about to get repainted but I was wondering if there would be any reason why I
    > shouldn't have the seat tube 'adjusted' at the same time. The problem is that there is a good 4 cm
    > of seat tube above
    the
    > top tube. This means that to get a good fistful of seat post to protrude above the seat tube, the
    > saddle ends up being a cm or two higher than it needs to be.

    Why do you need to have a "fistful" of seatpost showing? Just set the seat height the proper height
    for you and forget about the fact that some of it is covered by the seat tube collar.

    > This would be no big deal except that I think I would be a lot more comfortable sitting a cm or
    > two lower as well as being a little
    closer
    > to the bars. Are there any structural reasons why I couldn't just have a frame builder take 2 cm
    > off the tube before I get it repainted?
    >
    > Thanks in advance, Rob Strickland
     
  4. Russell

    Russell Guest

    "Robert Strickland" <[email protected]> wrote in message
    news:<[email protected]>...
    > I've got a frame I'm about to get repainted but I was wondering if there would be any reason why I
    > shouldn't have the seat tube 'adjusted' at the same time. The problem is that there is a good 4 cm
    > of seat tube above the top tube. This means that to get a good fistful of seat post to protrude
    > above the seat tube, the saddle ends up being a cm or two higher than it needs to be.

    Why does there need to be a "good fistful" of seatpost protruding, other than a perhaps cosmetic
    one? Couldn't you just lower the saddle one or two cm and be done with it? If anything, you could
    actually have the bike be lighter; since the seat tube extends up so far, you can cut off excess
    seatpost length that would be inside the tube, and not serving any structural purpose.
     
  5. A Muzi

    A Muzi Guest

    "Robert Strickland" <[email protected]> wrote in message
    news:[email protected]...
    > I've got a frame I'm about to get repainted but I was wondering if there would be any reason why I
    > shouldn't have the seat tube 'adjusted' at the same time. The problem is that there is a good 4 cm
    > of seat tube above the top tube. This means that to get a good fistful of seat post to protrude
    > above the seat tube, the saddle ends up being a cm or two higher than it needs to be. This would
    > be no big deal except that I think I would be a
    lot
    > more comfortable sitting a cm or two lower as well as being a little
    closer
    > to the bars. Are there any structural reasons why I couldn't just have a frame builder take 2 cm
    > off the tube before I get it repainted?

    Without knowing what frame it is, it probably could be trimmed, especially if it is steel. You
    should consult with a frame repair shop to see if there are any mitigating factors.

    But I see this as an aesthetic issue. You won't change your riding position by trimming the
    seat tube.

    Unless. . . Are you saying that you have your saddle higher than it should be because it cannot go
    low enough into the frame? That wouuld seem to indicate a frame that's overly large for you.

    When you say "closer to the bars" do you mean because lowering the saddle along a 74-degree
    line moves it forward? That small effect is lost in the noise of your saddle's fore-aft
    adjustment on the post.

    Do write again, perhaps with a photo link. It would seem that a fitting session is in order before
    the paint job.

    --
    Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971
     
  6. "Robert Strickland" <[email protected]> wrote in message
    news:<[email protected]>...
    > I've got a frame I'm about to get repainted but I was wondering if there would be any reason why I
    > shouldn't have the seat tube 'adjusted' at the same time. The problem is that there is a good 4 cm
    > of seat tube above the top tube. This means that to get a good fistful of seat post to protrude
    > above the seat tube, the saddle ends up being a cm or two higher than it needs to be.

    Sir, If you are worried about having a fistful of seatpost, why not just count a fistful of
    seapost/extended seat tube and call it good? Said fist is a sizing convention, no? Unless there is
    some unexplained virtue to having the ACTUAL aluminum seatpost showing the width of your hand, why
    hack up your frame? Brian Plaugher
     
  7. > Without knowing what frame it is, it probably could be trimmed, especially if it is steel. You
    > should consult with a frame repair shop to see if
    there
    > are any mitigating factors.
    >
    > But I see this as an aesthetic issue. You won't change your riding
    position
    > by trimming the seat tube.
    >
    > Unless. . . Are you saying that you have your saddle higher than it should be because it cannot go
    > low enough into the frame? That wouuld seem to indicate a frame that's overly large for you.
    >
    > When you say "closer to the bars" do you mean because lowering the saddle along a 74-degree line
    > moves it forward? That small effect is lost in the noise of your saddle's fore-aft adjustment on
    > the post.
    >
    > Do write again, perhaps with a photo link. It would seem that a fitting session is in order before
    > the paint job.
    >
    > --
    > Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

    Thanks for the comments Andrew (and others who've commented). The frame is steel and the main issue
    is fit but I think the frame is only marginally too big. I've been riding on this frame for a couple
    of years and I am able to get reasonably comfortable on it but only if I lower the seat post to just
    1 or 2 cm above the seat tube. For some time I've felt a little bit stretched, especially on long
    rides so I swapped out the original stem for one that brings the bars closer by about 1 1/2 cm. That
    seemed to help a lot. I also swapped the seatpost out for one that isn't set back quite as far but I
    haven't had a chance to really experiment with that yet. My main interest in shortening the seat
    tube is to give myself just a little bit more room to play with. The second issue is that with the
    seat post so low it's virtually impossible to affix things like saddlebags or u-lock brackets to the
    post, which I'd like to be able to do. Since the tube projects at least 2 cm higher above the top
    tube than any other frame I've owned it seemed like it shouldn't be a problem to take a couple of
    centimeters off. I've posted a couple of pics but since the frame is stripped I don't know how much
    they really help.

    www.invertebratadesigns.com/pics/st1.jpg www.invertebratadesigns.com/pics/st2.jpg

    Thanks, Rob
     
  8. In article <[email protected]>, Robert Strickland
    <[email protected]> wrote:
    >
    >www.invertebratadesigns.com/pics/st1.jpg www.invertebratadesigns.com/pics/st2.jpg

    Looks like you could easily reduce that exposed tubing by about half, maybe a little more. Not being
    able to see you and the bike I haven't a clue if it really fits you but shortening that tube is no
    big deal if that's what you want.
     
  9. A Muzi

    A Muzi Guest

    ([email protected]) offered:
    > > Without knowing what frame it is, it probably could be trimmed,
    especially
    > > if it is steel. You should consult with a frame repair shop to see if
    > there
    > > are any mitigating factors.
    > >
    > > But I see this as an aesthetic issue. You won't change your riding
    > position
    > > by trimming the seat tube.
    > >
    > > Unless. . . Are you saying that you have your saddle higher than it
    should
    > > be because it cannot go low enough into the frame? That wouuld seem to indicate a frame that's
    > > overly large for you.
    > >
    > > When you say "closer to the bars" do you mean because lowering the
    saddle
    > > along a 74-degree line moves it forward? That small effect is lost in
    the
    > > noise of your saddle's fore-aft adjustment on the post.
    > >
    > > Do write again, perhaps with a photo link. It would seem that a fitting session is in order
    > > before the paint job.

    "Robert Strickland" <[email protected]> wrote in message
    news:[email protected]...
    > Thanks for the comments Andrew (and others who've commented). The frame is steel and the main
    > issue is fit but I think the frame is only marginally
    too
    > big. I've been riding on this frame for a couple of years and I am able to get reasonably
    > comfortable on it but only if I lower the seat post to just
    1
    > or 2 cm above the seat tube. For some time I've felt a little bit
    stretched,
    > especially on long rides so I swapped out the original stem for one that brings the bars closer by
    > about 1 1/2 cm. That seemed to help a lot. I
    also
    > swapped the seatpost out for one that isn't set back quite as far but I haven't had a chance to
    > really experiment with that yet. My main interest
    in
    > shortening the seat tube is to give myself just a little bit more room to play with. The second
    > issue is that with the seat post so low it's
    virtually
    > impossible to affix things like saddlebags or u-lock brackets to the post, which I'd like to be
    > able to do. Since the tube projects at least 2 cm higher above the top tube than any other frame
    > I've owned it seemed like
    it
    > shouldn't be a problem to take a couple of centimeters off. I've posted a couple of pics but since
    > the frame is stripped I don't know how much they really help.
    >
    > www.invertebratadesigns.com/pics/st1.jpg www.invertebratadesigns.com/pics/st2.jpg

    That frame can be trimmed quite a bit and a seat binder brazed on the back. There are very handy
    cast "lugs" just for this sort of repair that include a binder and a ring around the top of the seat
    tube. Those require minimal height over the top tube as thet are designed for use after a failure.

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