Quill seat posts for MTB?

Folks,

In the old days they were available but can't find modern ones for MTB.

https://www.youtube.com/watch?v=5EkigpkVXLY

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Any hints who still carries that?

--
Regards, Joerg

http://www.analogconsultants.com/

On 12/2/2016 11:38 AM, Joerg wrote:
Folks,

In the old days they were available but can't find modern
ones for MTB.

https://www.youtube.com/watch?v=5EkigpkVXLY

Fixing a seat post only at the top (kind of) works for
regular bikes that aren't used on harsh turf but not for MTB
with heavy loads. Mine started creaking to no end and that's
probably not good for the frame. So I am looking for a
longer seat post but ideally with quill.

Any hints who still carries that?


We make them. We didn't come up in your web search?

http://www.yellowjersey.org/yampost.html


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

On 2016-12-02, AMuzi wrote:
On 12/2/2016 11:38 AM, Joerg wrote:
So I am looking for a longer seat post but ideally with quill.

We make them. We didn't come up in your web search?

http://www.yellowjersey.org/yampost.html

Nice. I'll remember that the next time I get the urge to buy
one of those sweet Moser Leader AX frames.

--
Gregory S. Sutter Mostly Harmless

http://zer0.org/~gsutter/

On 2016-12-02, Joerg wrote:

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Joerg,

99.9+% of all bicycles, made for all uses and types of loads, clamp
the seatpost at the top. I submit that you are on a wild goose
chase, and have several misconceptions.

A longer post usually means nothing, as the only area of the frame
that clamps down on the seatpost is the top 7-12cm. The post just
has to be inserted to its minimum-insertion line.

For similar reasons the quill seatpost is probably not a good idea
for your frame: the seat tube won't be shimmed as far down as the
quill will clamp, and isn't meant to take the forces that the quill
will apply.

On the seatpost clamp, too tight is often worse than too loose,
because while too loose results only in slipping, too tight can
damage the clamp (strip threads or snap the band), the seatpost
(crimping) or possibly even the frame. If the creaking you hear
has recently started, perhaps it is because the post-clamp interface
is no longer correct due to overtightening or an impact.

(Anecdote time: I once lightly dented a Thompson post (!) at the
clamp from an impact while riding. My butt didn't like it either.)

Therefore I recommend to you that you ensure your existing seatpost
clamp is still round and smooth; that your seatpost in the clamped
area is the same; that you grease the threads on the clamp's bolt;
that you lightly grease the seatpost where it touches the clamp and
the frame shim; and that you use a torque wrench when you tighten the
clamp.

--
Gregory S. Sutter Mostly Harmless

http://zer0.org/~gsutter/

On 12/2/2016 3:04 PM, Gregory Sutter wrote:
On 2016-12-02, Joerg wrote:

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Joerg,

99.9+% of all bicycles, made for all uses and types of loads, clamp
the seatpost at the top. I submit that you are on a wild goose
chase, and have several misconceptions.

A longer post usually means nothing, as the only area of the frame
that clamps down on the seatpost is the top 7-12cm. The post just
has to be inserted to its minimum-insertion line.

For similar reasons the quill seatpost is probably not a good idea
for your frame: the seat tube won't be shimmed as far down as the
quill will clamp, and isn't meant to take the forces that the quill
will apply.

On the seatpost clamp, too tight is often worse than too loose,
because while too loose results only in slipping, too tight can
damage the clamp (strip threads or snap the band), the seatpost
(crimping) or possibly even the frame. If the creaking you hear
has recently started, perhaps it is because the post-clamp interface
is no longer correct due to overtightening or an impact.

(Anecdote time: I once lightly dented a Thompson post (!) at the
clamp from an impact while riding. My butt didn't like it either.)

Therefore I recommend to you that you ensure your existing seatpost
clamp is still round and smooth; that your seatpost in the clamped
area is the same; that you grease the threads on the clamp's bolt;
that you lightly grease the seatpost where it touches the clamp and
the frame shim; and that you use a torque wrench when you tighten the
clamp.


All good points but I'll add that in modern thinwall steel
TIG frames, seatpost flex can be a significant problem.
Builders now recommend post insertion 2 diameters below the
lowest weld as excessive flex can lead to weld cracks.

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

On Fri, 02 Dec 2016 16:36:45 -0600, AMuzi wrote:

On 12/2/2016 3:04 PM, Gregory Sutter wrote:
On 2016-12-02, Joerg wrote:

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Joerg,

99.9+% of all bicycles, made for all uses and types of loads, clamp
the seatpost at the top. I submit that you are on a wild goose
chase, and have several misconceptions.

A longer post usually means nothing, as the only area of the frame
that clamps down on the seatpost is the top 7-12cm. The post just
has to be inserted to its minimum-insertion line.

For similar reasons the quill seatpost is probably not a good idea
for your frame: the seat tube won't be shimmed as far down as the
quill will clamp, and isn't meant to take the forces that the quill
will apply.

On the seatpost clamp, too tight is often worse than too loose,
because while too loose results only in slipping, too tight can
damage the clamp (strip threads or snap the band), the seatpost
(crimping) or possibly even the frame. If the creaking you hear
has recently started, perhaps it is because the post-clamp interface
is no longer correct due to overtightening or an impact.

(Anecdote time: I once lightly dented a Thompson post (!) at the
clamp from an impact while riding. My butt didn't like it either.)

Therefore I recommend to you that you ensure your existing seatpost
clamp is still round and smooth; that your seatpost in the clamped
area is the same; that you grease the threads on the clamp's bolt;
that you lightly grease the seatpost where it touches the clamp and
the frame shim; and that you use a torque wrench when you tighten the
clamp.


All good points but I'll add that in modern thinwall steel
TIG frames, seatpost flex can be a significant problem.
Builders now recommend post insertion 2 diameters below the
lowest weld as excessive flex can lead to weld cracks.

Seat Post flex, or Seat Tube flex?
--
cheers,

John B.

On Fri, 02 Dec 2016 09:38:30 -0800, Joerg
wrote:

Folks,

In the old days they were available but can't find modern ones for MTB.

https://www.youtube.com/watch?v=5EkigpkVXLY

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Any hints who still carries that?

Why is clamping the seat post with a clamp at the top actually
different from clamping the seat post at the bottom?

Theoretically at least the seat post is supposed to be sliding fit in
the seat tube with minimal play so clamping at one end is very much
the same as clamping at the other.
--
cheers,

John B.

On Friday, December 2, 2016 at 4:38:08 PM UTC-8, John B. wrote:
On Fri, 02 Dec 2016 09:38:30 -0800, Joerg
wrote:

Folks,

In the old days they were available but can't find modern ones for MTB.

https://www.youtube.com/watch?v=5EkigpkVXLY

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Any hints who still carries that?

Why is clamping the seat post with a clamp at the top actually
different from clamping the seat post at the bottom?

Theoretically at least the seat post is supposed to be sliding fit in
the seat tube with minimal play so clamping at one end is very much
the same as clamping at the other.


- Because if clamped at the top, the pinch bolt will be under tension, and able to absorb the tension put on it by the post, before the welds can experience it.

Google brandt+pretension

On Fri, 2 Dec 2016 17:11:21 -0800 (PST), Doug Landau
wrote:

On Friday, December 2, 2016 at 4:38:08 PM UTC-8, John B. wrote:
On Fri, 02 Dec 2016 09:38:30 -0800, Joerg
wrote:

Folks,

In the old days they were available but can't find modern ones for MTB.

https://www.youtube.com/watch?v=5EkigpkVXLY

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Any hints who still carries that?

Why is clamping the seat post with a clamp at the top actually
different from clamping the seat post at the bottom?

Theoretically at least the seat post is supposed to be sliding fit in
the seat tube with minimal play so clamping at one end is very much
the same as clamping at the other.


- Because if clamped at the top, the pinch bolt will be under tension, and able to absorb the tension put on it by the post, before the welds can experience it.

Google brandt+pretension

Certainly the pinch bolt is tightened. But is the pinch bolt, in some
manner independent of all else? Just floating there in space absorbing
all stresses and strains imposed on it? Or is it simply a clamp that
transfers loads imposed on it to the bicycle frame.

Is the fact that all seat posts have some minimum insertion limits
important? Given that the seat clamp tension bolt "absorbs the
tension"?
--
cheers,

John B.

On 12/2/2016 5:58 PM, John B. wrote:
On Fri, 02 Dec 2016 16:36:45 -0600, AMuzi wrote:

On 12/2/2016 3:04 PM, Gregory Sutter wrote:
On 2016-12-02, Joerg wrote:

Fixing a seat post only at the top (kind of) works for regular bikes
that aren't used on harsh turf but not for MTB with heavy loads. Mine
started creaking to no end and that's probably not good for the frame.
So I am looking for a longer seat post but ideally with quill.

Joerg,

99.9+% of all bicycles, made for all uses and types of loads, clamp
the seatpost at the top. I submit that you are on a wild goose
chase, and have several misconceptions.

A longer post usually means nothing, as the only area of the frame
that clamps down on the seatpost is the top 7-12cm. The post just
has to be inserted to its minimum-insertion line.

For similar reasons the quill seatpost is probably not a good idea
for your frame: the seat tube won't be shimmed as far down as the
quill will clamp, and isn't meant to take the forces that the quill
will apply.

On the seatpost clamp, too tight is often worse than too loose,
because while too loose results only in slipping, too tight can
damage the clamp (strip threads or snap the band), the seatpost
(crimping) or possibly even the frame. If the creaking you hear
has recently started, perhaps it is because the post-clamp interface
is no longer correct due to overtightening or an impact.

(Anecdote time: I once lightly dented a Thompson post (!) at the
clamp from an impact while riding. My butt didn't like it either.)

Therefore I recommend to you that you ensure your existing seatpost
clamp is still round and smooth; that your seatpost in the clamped
area is the same; that you grease the threads on the clamp's bolt;
that you lightly grease the seatpost where it touches the clamp and
the frame shim; and that you use a torque wrench when you tighten the
clamp.


All good points but I'll add that in modern thinwall steel
TIG frames, seatpost flex can be a significant problem.
Builders now recommend post insertion 2 diameters below the
lowest weld as excessive flex can lead to weld cracks.

Seat Post flex, or Seat Tube flex?


Pithy observation.
Seat post flex would have no significance if not for seat
tube flex in the hard areas adjacent to the weld

http://www.yellowjersey.org/photosfr...st/wiltaxi.jpg

Interestingly cracks these thin hard steels seem to progress
perpendicular to the weld bead.

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