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Main
Date: 27 Jun 2007 20:37:05
From: meb
Subject: seatpost extension
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I have a low end folding bike with a 400mm x 25.4 seatpost.
I've damaged and weakened the top of the seattube by riding the setpost
above the insertion line (I've also bowed the seatpost). Therefore I
have to ovecompensate by dropping the tube further down into the
seattube.
Was looking for an interim temp fix for a seatpost extension before
this bike is converted into a folding upright-recumbent redundant (ala
Reynolds Redundant).
Option 1: get a 28-30mm seatpost and outersleve about the old
seatpost.
Option 2: get a 21mm seatpost and inner sleve it within the old
seatpost.
Option 3: Take 3 muffler clamps and juxtapose two seatposts in
overlapping position using 2 claims about both and a 3rd below?
Option 4: Go to Home Depot/Lowes and cut a heavy 25.4 in o.d. pipe to
about 600-700 mm.
Another other options?
--
meb
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Date: 27 Jun 2007 22:46:09
From: A Muzi
Subject: Re: seatpost extension
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meb wrote:
> I have a low end folding bike with a 400mm x 25.4 seatpost.
> I've damaged and weakened the top of the seattube by riding the setpost
> above the insertion line (I've also bowed the seatpost). Therefore I
> have to ovecompensate by dropping the tube further down into the
> seattube.
>
> Was looking for an interim temp fix for a seatpost extension before
> this bike is converted into a folding upright-recumbent redundant (ala
> Reynolds Redundant).
>
> Option 1: get a 28-30mm seatpost and outersleve about the old
> seatpost.
>
> Option 2: get a 21mm seatpost and inner sleve it within the old
> seatpost.
>
> Option 3: Take 3 muffler clamps and juxtapose two seatposts in
> overlapping position using 2 claims about both and a 3rd below?
>
> Option 4: Go to Home Depot/Lowes and cut a heavy 25.4 in o.d. pipe to
> about 600-700 mm.
>
>
> Another other options?
Option 4 seems best to me. Although Nitto has one 400mm forged model (
not 25.4 sadly) most longish aluminum posts have a checkered history.
The ability to get adequate insertion is a real plus too.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 30 Jun 2007 05:23:38
From: meb
Subject: Re: seatpost extension
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A Muzi Wrote:
> meb wrote:
> > I have a low end folding bike with a 400mm x 25.4 seatpost.
> > I've damaged and weakened the top of the seattube by riding th
> setpost
> > above the insertion line (I've also bowed the seatpost). Therefor
> I
> > have to ovecompensate by dropping the tube further down into the
> > seattube.
> >
> > Was looking for an interim temp fix for a seatpost extension before
> > this bike is converted into a folding upright-recumbent redundan
> (ala
> > Reynolds Redundant).
> >
> > Option 1: get a 28-30mm seatpost and outersleve about the old
> > seatpost.
> >
> > Option 2: get a 21mm seatpost and inner sleve it within the old
> > seatpost.
> >
> > Option 3: Take 3 muffler clamps and juxtapose two seatposts in
> > overlapping position using 2 claims about both and a 3rd below?
> >
> > Option 4: Go to Home Depot/Lowes and cut a heavy 25.4 in o.d. pip
> to
> > about 600-700 mm.
> >
> >
> > Another other options?
>
> Option 4 seems best to me. Although Nitto has one 400mm forged model (
> not 25.4 sadly) most longish aluminum posts have a checkered history.
> The ability to get adequate insertion is a real plus too.
>
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
Gave option 4 a try. Thanks.
I was able to get a 24 inch x 7/8 inch O.D. 1/2 inch I.D. galvanize
steel pipe and shim it out (although I still need more shimming). Wit
max insert, I have about 150 mm inserted and 450 mm protruding and a
about 1 inch higher than preferred, so I'll see if I adapt to the sea
height before cutting off a couple of inches. 3/4 I.D. and 1 1/8 O.D
was also available, but I didn't think I could push that into th
seattube.
I am experience more oscilation-not sure yet if its play in the shim
or flex of the pipe or rear suspension pogoing with the further rea
seat position-although I'm now sitting with the suspension trave
bottomed out.
The folder is a monotube design with the folding monotube being th
only connection between the headtube and cranks. I'm wondering if
ought consider running the cable-lock between the seat and the hea
tube as a guyline for extra support with this longer seatpost
--
meb
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Date: 29 Jun 2007 00:33:34
From: meb
Subject: Re: seatpost extension
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A Muzi Wrote:
> meb wrote:
> > I have a low end folding bike with a 400mm x 25.4 seatpost.
> > I've damaged and weakened the top of the seattube by riding th
> setpost
> > above the insertion line (I've also bowed the seatpost). Therefor
> I
> > have to ovecompensate by dropping the tube further down into the
> > seattube.
> >
> > Was looking for an interim temp fix for a seatpost extension before
> > this bike is converted into a folding upright-recumbent redundan
> (ala
> > Reynolds Redundant).
> >
> > Option 1: get a 28-30mm seatpost and outersleve about the old
> > seatpost.
> >
> > Option 2: get a 21mm seatpost and inner sleve it within the old
> > seatpost.
> >
> > Option 3: Take 3 muffler clamps and juxtapose two seatposts in
> > overlapping position using 2 claims about both and a 3rd below?
> >
> > Option 4: Go to Home Depot/Lowes and cut a heavy 25.4 in o.d. pip
> to
> > about 600-700 mm.
> >
> >
> > Another other options?
>
> Option 4 seems best to me. Although Nitto has one 400mm forged model (
> not 25.4 sadly) most longish aluminum posts have a checkered history.
> The ability to get adequate insertion is a real plus too.
>
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971
The seatpost I have is not aluminum but steel-so while it is bowed, I'
not that concerned with its integritty although there a question how fa
I can successfully insert it without straightening.
As my 400mm seatpost is way too short, a 400 mm Nitto wouldn't hav
done any better, I'd need at least 600mm-probably something I'll onl
find on some other folders (Dahon uses 27.2 aluminum on its lon
seatpost so its diameter is incompatible; Downtube use 27.2 and 30.
diameter on their 450mm seatposts)
--
meb
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