Shortening a seat tube



Status
Not open for further replies.
R

Robert Strickla

Guest
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
 
P

Paul Southworth

Guest
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
 
O

One Of The Six

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 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
 
R

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.
 
A

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
 
B

Brian Plaugher

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.

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
 
R

Robert Strickla

Guest
> 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
 
P

Paul Southworth

Guest
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.
 
A

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
 
Status
Not open for further replies.