Carbon seat post recommendation ?

Ron Ruff wrote:

jim beam wrote:

"I don't think... " so you don't have one then? is that a qualificaton
for advice? or is it just opinion based on other r.b.t blowhards?

Yes, I don't have one...

And no, I'm basing it on on the fact that the seatpost does not deflect
enough to cause a difference in "feel", or damping.

That depends on several factors, including the length of exposed post,
diameter, wall thickness and material of the post, rider weight, and
(if the post is CFRP) the lay of the fibers in the post.

I think it's safe to generalize the way you have when the bike in
question has traditional geometry and is traditionally sized (with a
level top tube and a "fistful" of exposed post). Throw a sloping top
tube or a too-small frame into the mix, and the post can easily flex
enough to make a difference in perceived ride quality. And it's clear
to me that flex in the seatpost can affect comfort substantially.

CFRP tubing can be amazingly stiffer or way more flexible than metal
tubing of equal weight, depending on the density and orientation of
fibers in its structure. So it's not accurate to characterize CFRP
posts as a whole for their ability or inability to flex noticeably.

What a CFRP post will *not* do is damp vibration significantly. CFRP,
like metal, will ring for hundreds of cycles if struck, so there is
obviously no significant damping there for our purposes. What keeps it
from ringing while you ride is the portion of the system that does have
damping qualities: tires, saddle and (more importantly) your body.

As a side note, I recall Zinn asking two Italian companies if their
carbon bars and stems would provide good damping. They replied, "No,
they are quite stiff". But of course Easton said, "Yes". Maybe the
whole damping BS is only for US consumption...

Because of the nature of CFRP materials, they could all have been
correct. More likely, they were just telling Lennard Zinn what they
thought would impress him, but that's another matter.

This all misses the point in that the seatpost is really the wrong
place to try to enhance a bike's comfort. A good saddle will make a
much bigger difference in comfort for a much lower cost.

Chalo Colina

Jeff Starr wrote:
On Mon, 21 Nov 2005 23:40:10 GMT, "Jay S. Hill"
wrote:


Have you ever tried crushing a CF seatpost?

No, but I did it accidentally by overtightening the seat binder bolt.
From what I've read, and after talking to a very good mechanic (Nello)
here in Austin, it's not that unusual. He doesn't reccommend carbon
posts because of this.

Chalo wrote:
Ron Ruff wrote:

jim beam wrote:

"I don't think... " so you don't have one then? is that a qualificaton
for advice? or is it just opinion based on other r.b.t blowhards?

Yes, I don't have one...

And no, I'm basing it on on the fact that the seatpost does not deflect
enough to cause a difference in "feel", or damping.


That depends on several factors, including the length of exposed post,
diameter, wall thickness and material of the post, rider weight, and
(if the post is CFRP) the lay of the fibers in the post.

I think it's safe to generalize the way you have when the bike in
question has traditional geometry and is traditionally sized (with a
level top tube and a "fistful" of exposed post). Throw a sloping top
tube or a too-small frame into the mix, and the post can easily flex
enough to make a difference in perceived ride quality. And it's clear
to me that flex in the seatpost can affect comfort substantially.

CFRP tubing can be amazingly stiffer or way more flexible than metal
tubing of equal weight, depending on the density and orientation of
fibers in its structure. So it's not accurate to characterize CFRP
posts as a whole for their ability or inability to flex noticeably.

What a CFRP post will *not* do is damp vibration significantly.

damp is the wrong word. attenuate is better.

CFRP,
like metal, will ring for hundreds of cycles if struck,

for some frequencies, yes. not others. the transmission spectrum is
radically different.

so there is
obviously no significant damping there for our purposes.

these "so obviously" arguments make no sense when based on a false
assumption.

What keeps it
from ringing while you ride is the portion of the system that does have
damping qualities: tires, saddle and (more importantly) your body.


As a side note, I recall Zinn asking two Italian companies if their
carbon bars and stems would provide good damping. They replied, "No,
they are quite stiff". But of course Easton said, "Yes". Maybe the
whole damping BS is only for US consumption...


Because of the nature of CFRP materials, they could all have been
correct. More likely, they were just telling Lennard Zinn what they
thought would impress him, but that's another matter.

This all misses the point in that the seatpost is really the wrong
place to try to enhance a bike's comfort. A good saddle will make a
much bigger difference in comfort for a much lower cost.

Chalo Colina

rs wrote:
I've got a low-end road bike, Giant OCR3 and would like to get a little more
damping, thinking a carbon seat post would help. Obviously I don't need the
lightest but is there a brand recommendation for a fairly inexpensive and
decent one for a road bike?

I needed less setback so I sold my Thomson Al seatpost & got a USE Alien
carbon one hoping for a more damped ride in the bargain. I can't feel
the diff. I think there is a lot of nonesense in the Great Materials
Debate.

I'd look for other things such as seat adjustablity in a post. My Alien
isn't very adjustable which might have turned out badly, but the
standard place of the seat worked out ok for me.

I think it's safe to generalize the way you have when the bike in
question has traditional geometry and is traditionally sized (with a
level top tube and a "fistful" of exposed post). Throw a sloping top
tube or a too-small frame into the mix, and the post can easily flex
enough to make a difference in perceived ride quality. And it's clear
to me that flex in the seatpost can affect comfort substantially.


The OCR series are Giant's 'non-racing' compact bikes. TT slopes
fairly dramatically.

SYJ

On Mon, 21 Nov 2005 22:12:18 -0500, John Forrest Tomlinson wrote:

On Mon, 21 Nov 2005 21:27:33 -0500, Matt O'Toole
wrote:

Shock-absorbing saddles
like the Turbomatic and Koobi *do* work. They offer a cm or so flex in
exactly the direction that's helpful, rather than the sideways waggle of a
flexy carbon or Ti seatpost. Until very recently, Turbomatics were still
popular among pros.

Stil -- this is 2004 at the earliest, or maybe this year:

http://www.cervelo.com/images/2004/v...ist%20Team.jpg

I can't really see it in that picture, but I'll take your word for it.

Turbomatics seem to be universally liked, by newbies and pros alike. This
is rare with saddles.

Too bad they've been discontinued!

BTW, Mountain Bike Action magazine tested various suspension saddles
several years ago. I was surprised how much travel they provided.

Matt O.

In article , says...

just curious--what would be your opinion of carbon handlebars? People have
been telling me to upgrade to one as they are supposed to be great shock
absorbers. Is that true?

I'm still trying to absorb the shock from the asking price.
--------------
Alex

Matt O'Toole wrote:
On Mon, 21 Nov 2005 22:12:18 -0500, John Forrest Tomlinson wrote:

On Mon, 21 Nov 2005 21:27:33 -0500, Matt O'Toole
wrote:

Shock-absorbing saddles
like the Turbomatic and Koobi *do* work. They offer a cm or so
flex in exactly the direction that's helpful, rather than the
sideways waggle of a flexy carbon or Ti seatpost. Until very
recently, Turbomatics were still popular among pros.

Stil -- this is 2004 at the earliest, or maybe this year:

http://www.cervelo.com/images/2004/v...ist%20Team.jpg

I can't really see it in that picture, but I'll take your word for it.

Thought I was missing something; thanks!

"Matt O'Toole" wrote in message
news
On Mon, 21 Nov 2005 22:12:18 -0500, John Forrest Tomlinson wrote:

On Mon, 21 Nov 2005 21:27:33 -0500, Matt O'Toole
wrote:

Shock-absorbing saddles
like the Turbomatic and Koobi *do* work. They offer a cm or so flex in
exactly the direction that's helpful, rather than the sideways waggle of a
flexy carbon or Ti seatpost. Until very recently, Turbomatics were still
popular among pros.

Stil -- this is 2004 at the earliest, or maybe this year:

http://www.cervelo.com/images/2004/v...ist%20Team.jpg

I can't really see it in that picture, but I'll take your word for it.

Turbomatics seem to be universally liked, by newbies and pros alike. This
is rare with saddles.

Too bad they've been discontinued!

BTW, Mountain Bike Action magazine tested various suspension saddles
several years ago. I was surprised how much travel they provided.

Matt O.


I've been riding a Turbomatic for about 3000 miles and have been very pleased
with it. I tired about five other saddles and the Turbomatic was the only one
that worked for me. It is a much heavier saddle and it does occasionally make
wierd noises I guess from the suspension. On one of my rides I cross a wooden
bridge and I am always amazed at the shock absorbing the saddle provides. The
Turbomatic is still sold at Excel Sports for $80 and I have seen used ones on
Ebay.

Neal

Matt O'Toole wrote:
On Mon, 21 Nov 2005 22:12:18 -0500, John Forrest Tomlinson wrote:


On Mon, 21 Nov 2005 21:27:33 -0500, Matt O'Toole
wrote:


Shock-absorbing saddles
like the Turbomatic and Koobi *do* work. They offer a cm or so flex in
exactly the direction that's helpful, rather than the sideways waggle of a
flexy carbon or Ti seatpost. Until very recently, Turbomatics were still
popular among pros.



Stil -- this is 2004 at the earliest, or maybe this year:



http://www.cervelo.com/images/2004/v...ist%20Team.jpg


I can't really see it in that picture, but I'll take your word for it.

Turbomatics seem to be universally liked, by newbies and pros alike. This
is rare with saddles.

Too bad they've been discontinued!

BTW, Mountain Bike Action magazine tested various suspension saddles
several years ago. I was surprised how much travel they provided.

Matt O.

The Selle Italia "Trimatic" is the most comfortable saddle I have ever
used (out of a dozen, including Flite, WTB SST, and 2 Brooks). I found I
could ride a 400K (250 mi) right out of the box without soreness --
never did that before.