carbon seatposts in carbon frames - TLC?

Yuri Budilov said:

Hello everyone

My LBS said I need to pull out my carbon post from my carbon frame and wipe
both with clean dry cloth every 1-3 months or riding (particularly if I ride
in wet weather) to avoid the two "fusing" together permanently (very
expensive situation since crushing carbon seat post would be the only way
out in such a situation).

Has anyone heard or seen such a thing? Is it a real risk or my LBS is overly
paranoid? I am talking about 2005 Trek Madone 5.9 btw, if it makes any
difference.

Furthermore, how paranoid should I be when I tighten the bolt-clamp when
securing my carbon seat post to avoid crushing the post or the carbon frame
in which it resides? Do I really need to buy a torque wrench?

thanks

Good advice, I just saw a carbon post permanently bonded to a Trek
5900.
Also, turn the clamp around 180 degrees. It will help to keep the seat
tube hole rounder when you tighten the clamp to prevent crushing. Good
idea for any seat post clamp and carbon post.

Qui si parla Campagnolo said:

Yuri Budilov said:

Hello everyone

My LBS said I need to pull out my carbon post from my carbon frame and wipe
both with clean dry cloth every 1-3 months or riding (particularly if I ride
in wet weather) to avoid the two "fusing" together permanently (very
expensive situation since crushing carbon seat post would be the only way
out in such a situation).

Has anyone heard or seen such a thing? Is it a real risk or my LBS is overly
paranoid? I am talking about 2005 Trek Madone 5.9 btw, if it makes any
difference.

Furthermore, how paranoid should I be when I tighten the bolt-clamp when
securing my carbon seat post to avoid crushing the post or the carbon frame
in which it resides? Do I really need to buy a torque wrench?

thanks

Good advice, I just saw a carbon post permanently bonded to a Trek
5900.
Also, turn the clamp around 180 degrees. It will help to keep the seat
tube hole rounder when you tighten the clamp to prevent crushing. Good
idea for any seat post clamp and carbon post.

Are you saying to place the clamp slot 180 degrees from the seat tube
slot? Could you please explain a) how this is superior and b) why it
wouldn't crush carbon composite material of the seat tube at the clamp
slot anyway (or perhaps be more inclined to)?

Curiously, I saw a Willier (sp?) carbon frame the other day with four
seat tube slots and a clamp with a collet.

Perhaps something like a handlebar clamp pulling two halves together?

Robin Hubert

"Robin Hubert" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Qui si parla Campagnolo said:

Yuri Budilov said:

Hello everyone

My LBS said I need to pull out my carbon post from my carbon frame and
wipe
both with clean dry cloth every 1-3 months or riding (particularly if I
ride
in wet weather) to avoid the two "fusing" together permanently (very
expensive situation since crushing carbon seat post would be the only way
out in such a situation).

Has anyone heard or seen such a thing? Is it a real risk or my LBS is
overly
paranoid? I am talking about 2005 Trek Madone 5.9 btw, if it makes any
difference.

Furthermore, how paranoid should I be when I tighten the bolt-clamp when
securing my carbon seat post to avoid crushing the post or the carbon
frame
in which it resides? Do I really need to buy a torque wrench?

thanks

Good advice, I just saw a carbon post permanently bonded to a Trek
5900.
Also, turn the clamp around 180 degrees. It will help to keep the seat
tube hole rounder when you tighten the clamp to prevent crushing. Good
idea for any seat post clamp and carbon post.

Are you saying to place the clamp slot 180 degrees from the seat tube
slot? Could you please explain a) how this is superior and b) why it
wouldn't crush carbon composite material of the seat tube at the clamp
slot anyway (or perhaps be more inclined to)?

Curiously, I saw a Willier (sp?) carbon frame the other day with four seat
tube slots and a clamp with a collet.

Perhaps something like a handlebar clamp pulling two halves together?

Robin Hubert

Hi

I don't know the answers to your questions but I had a carbon Specialized
Roubaix with carbon seat post and their instructions were exactly as the
first reply said - bolt to be on the opposite side to where the
crack/slit/whatever in the seat tube is - to prevent crashing the post. So I
asked my LBS about this rule for Trek Madone and they said that Trek
instructions were to place the bolt on the same side as crack/slit/etc not
on opposite side. This is very puzzling for me too! But I hate to break Trek
warranty by spinning the clamp around 180 degrees. Perhaps someone can send
Trek support an e-mail question? I would if I knew where to send it to.....

Robin Hubert said:

Qui si parla Campagnolo wrote:

Quoted message said:

Are you saying to place the clamp slot 180 degrees from the seat tube
slot? Could you please explain a) how this is superior and b) why it
wouldn't crush carbon composite material of the seat tube at the clamp
slot anyway (or perhaps be more inclined to)?

Curiously, I saw a Willier (sp?) carbon frame the other day with four
seat tube slots and a clamp with a collet.

Perhaps something like a handlebar clamp pulling two halves together?

Robin Hubert

When the first gen Campag carbon posts were getting cracked at the back
where the split was in the seat tube and the clamp, Campag suggested
turning the clamp around 180 degrees to help keep the 'hole' for the SP
more round rather than oval. helped for the thin-ish Campag post, would
work for others.

Not trying to argue with you Robin, and the tone of your post suggests
that I must defend the practice somehow.

I do it on all carbon posts, I discourage carbon posts in frames w/o a
clamp.

Qui si parla Campagnolo said:

Robin Hubert said:

Qui si parla Campagnolo wrote:

Quoted message said:

Are you saying to place the clamp slot 180 degrees from the seat tube
slot? Could you please explain a) how this is superior and b) why it
wouldn't crush carbon composite material of the seat tube at the clamp
slot anyway (or perhaps be more inclined to)?

Curiously, I saw a Willier (sp?) carbon frame the other day with four
seat tube slots and a clamp with a collet.

Perhaps something like a handlebar clamp pulling two halves together?

Robin Hubert

When the first gen Campag carbon posts were getting cracked at the back
where the split was in the seat tube and the clamp, Campag suggested
turning the clamp around 180 degrees to help keep the 'hole' for the SP
more round rather than oval. helped for the thin-ish Campag post, would
work for others.

Not trying to argue with you Robin, and the tone of your post suggests
that I must defend the practice somehow.

I do it on all carbon posts, I discourage carbon posts in frames w/o a
clamp.

No defense necessary. I just like explanations for things so I
understand. Just because someone (even the "experts" at Campagnolo)
said so carries little weight, in my mind. Personally, I don't
understand how turning the clamp around 180 degrees will help. The
inner diameter of the seat tube must be reduced somehow to clamp the
seatpost, and I don't think compressing the seat tube is the better
alternative. The diameter has to be made smaller, and that's what the
split clamp does. Unfortunately, it also provides uneven, point loading
at the edges of the slot.

I still think most damaged carbon posts are due to a) poor tolerances of
either seat tube or post, or a combination of both and b) knuckleheaded
operators who think tighter is better without regard to the side-effects.

Ever try to put a carbon post into an older Aegis with the internal
pinch-design seat clamp? Aegis wasn't even aware it'd be a problem.

All said, I think carbon posts are a bad idea on modern frame designs.
Something different needs to be explored, such as the example I listed
above (four slots and collet). Maybe two-bolt clamps at the slot (aka,
a stem on carbon steerer? The folks at Waterford agree. They refuse to
recommend a carbon post for their frames.

Oh, and I apologize for cracking wise, but all too often the egos float
around this place and legitimate answers to legitimate questions fall to
the wayside (as was the case to which I responded so wise-assed).

Robin Hubert

Quoted message said:

No defense necessary. I just like explanations for things so I
understand. Just because someone (even the "experts" at Campagnolo) said
so carries little weight, in my mind. Personally, I don't understand how
turning the clamp around 180 degrees will help. The inner diameter of the
seat tube must be reduced somehow to clamp the seatpost, and I don't think
compressing the seat tube is the better alternative. The diameter has to
be made smaller, and that's what the split clamp does. Unfortunately, it
also provides uneven, point loading at the edges of the slot.

Robin: Peter's correct that it's generally a good idea to reverse the seat
clamps. The problem comes when the slot in the seat clamp lines up with the
slot in the frame. In both cases they try to deform (point load, as you
mention), increase pressure on that one particular spot. You don't want to
increase pressure on a spot that's already suffering from increased
pressure, and keeping the slots from lining up prevents that. What Trek is
doing now is creating a seat clamp that has a diagonal slot, so it can still
be placed normally (without putting extra pressure right on the edge of the
frame slots).

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

"Robin Hubert" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Qui si parla Campagnolo said:

Robin Hubert said:

Qui si parla Campagnolo wrote:

Quoted message said:

Are you saying to place the clamp slot 180 degrees from the seat tube
slot? Could you please explain a) how this is superior and b) why it
wouldn't crush carbon composite material of the seat tube at the clamp
slot anyway (or perhaps be more inclined to)?

Curiously, I saw a Willier (sp?) carbon frame the other day with four
seat tube slots and a clamp with a collet.

Perhaps something like a handlebar clamp pulling two halves together?

Robin Hubert

When the first gen Campag carbon posts were getting cracked at the back
where the split was in the seat tube and the clamp, Campag suggested
turning the clamp around 180 degrees to help keep the 'hole' for the SP
more round rather than oval. helped for the thin-ish Campag post, would
work for others.

Not trying to argue with you Robin, and the tone of your post suggests
that I must defend the practice somehow.

I do it on all carbon posts, I discourage carbon posts in frames w/o a
clamp.

No defense necessary. I just like explanations for things so I
understand. Just because someone (even the "experts" at Campagnolo) said
so carries little weight, in my mind. Personally, I don't understand how
turning the clamp around 180 degrees will help. The inner diameter of the
seat tube must be reduced somehow to clamp the seatpost, and I don't think
compressing the seat tube is the better alternative. The diameter has to
be made smaller, and that's what the split clamp does. Unfortunately, it
also provides uneven, point loading at the edges of the slot.

I still think most damaged carbon posts are due to a) poor tolerances of
either seat tube or post, or a combination of both and b) knuckleheaded
operators who think tighter is better without regard to the side-effects.

Ever try to put a carbon post into an older Aegis with the internal
pinch-design seat clamp? Aegis wasn't even aware it'd be a problem.

All said, I think carbon posts are a bad idea on modern frame designs.
Something different needs to be explored, such as the example I listed
above (four slots and collet). Maybe two-bolt clamps at the slot (aka, a
stem on carbon steerer? The folks at Waterford agree. They refuse to
recommend a carbon post for their frames.

Oh, and I apologize for cracking wise, but all too often the egos float
around this place and legitimate answers to legitimate questions fall to
the wayside (as was the case to which I responded so wise-assed).

Robin Hubert

Quoted message said:

My LBS said I need to pull out my carbon post from my carbon frame and

wipe

Quoted message said:

both with clean dry cloth every 1-3 months or riding (particularly if I

ride

Quoted message said:

in wet weather) to avoid the two "fusing" together permanently (very
expensive situation since crushing carbon seat post would be the only way
out in such a situation).

Put grease on the carbon post, and it'll glue it to the frame, and then
you won't need a clamp.

"Mike Jacoubowsky" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Robin: Peter's correct that it's generally a good idea to reverse the seat
clamps. The problem comes when the slot in the seat clamp lines up with
the slot in the frame. In both cases they try to deform (point load, as
you mention), increase pressure on that one particular spot. You don't
want to increase pressure on a spot that's already suffering from
increased pressure, and keeping the slots from lining up prevents that.
What Trek is doing now is creating a seat clamp that has a diagonal slot,
so it can still be placed normally (without putting extra pressure right
on the edge of the frame slots).

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

Mike

on a 2005 Madone do you recommend I reverse the seat post clamp 180 degrees
so that the tighten-bolt is on the opposite side of the seat tube split?

My LBS mounted clamp with the bolt on the same side as the split in the seat
tube saying this is as per Trek instructions. And I really do not want to
crush that Race X Lite carbon post (or the frame seat tube!)....

thank you for your assistance!

Robin Hubert said:

Qui si parla Campagnolo said:

Robin Hubert said:

Qui si parla Campagnolo wrote:

Quoted message said:

Are you saying to place the clamp slot 180 degrees from the seat tube
slot? Could you please explain a) how this is superior and b) why it
wouldn't crush carbon composite material of the seat tube at the clamp
slot anyway (or perhaps be more inclined to)?

Curiously, I saw a Willier (sp?) carbon frame the other day with four
seat tube slots and a clamp with a collet.

Perhaps something like a handlebar clamp pulling two halves together?

Robin Hubert

When the first gen Campag carbon posts were getting cracked at the back
where the split was in the seat tube and the clamp, Campag suggested
turning the clamp around 180 degrees to help keep the 'hole' for the SP
more round rather than oval. helped for the thin-ish Campag post, would
work for others.

Not trying to argue with you Robin, and the tone of your post suggests
that I must defend the practice somehow.

I do it on all carbon posts, I discourage carbon posts in frames w/o a
clamp.

No defense necessary. I just like explanations for things so I
understand. Just because someone (even the "experts" at Campagnolo)
said so carries little weight, in my mind. Personally, I don't
understand how turning the clamp around 180 degrees will help.

Then don't do it...

The

Quoted message said:

inner diameter of the seat tube must be reduced somehow to clamp the
seatpost, and I don't think compressing the seat tube is the better
alternative. The diameter has to be made smaller, and that's what the
split clamp does. Unfortunately, it also provides uneven, point loading
at the edges of the slot.

I still think most damaged carbon posts are due to a) poor tolerances of
either seat tube or post, or a combination of both and b) knuckleheaded
operators who think tighter is better without regard to the side-effects.

Ever try to put a carbon post into an older Aegis with the internal
pinch-design seat clamp? Aegis wasn't even aware it'd be a problem.

All said, I think carbon posts are a bad idea on modern frame designs.
Something different needs to be explored, such as the example I listed
above (four slots and collet). Maybe two-bolt clamps at the slot (aka,
a stem on carbon steerer? The folks at Waterford agree. They refuse to
recommend a carbon post for their frames.

Oh, and I apologize for cracking wise, but all too often the egos float
around this place and legitimate answers to legitimate questions fall to
the wayside (as was the case to which I responded so wise-assed).

Robin Hubert

Mike Jacoubowsky said:

Quoted message said:

No defense necessary. I just like explanations for things so I
understand. Just because someone (even the "experts" at Campagnolo) said
so carries little weight, in my mind. Personally, I don't understand how
turning the clamp around 180 degrees will help. The inner diameter of the
seat tube must be reduced somehow to clamp the seatpost, and I don't think
compressing the seat tube is the better alternative. The diameter has to
be made smaller, and that's what the split clamp does. Unfortunately, it
also provides uneven, point loading at the edges of the slot.

Robin: Peter's correct that it's generally a good idea to reverse the seat
clamps. The problem comes when the slot in the seat clamp lines up with the
slot in the frame. In both cases they try to deform (point load, as you
mention), increase pressure on that one particular spot. You don't want to
increase pressure on a spot that's already suffering from increased
pressure, and keeping the slots from lining up prevents that. What Trek is
doing now is creating a seat clamp that has a diagonal slot, so it can still
be placed normally (without putting extra pressure right on the edge of the
frame slots).

Gee just like the one from Campagnolo, ya know Robin those 'experts'
that don't know anythin? I guess if it's from Trek, it's a good idea
but if from Campagnolo, bad idea to you.

Quoted message said:

--Mike-- Chain Reaction Bicycles

Quoted message said:

Quoted message said:

My LBS said I need to pull out my carbon post from my carbon frame and

wipe

Quoted message said:

both with clean dry cloth every 1-3 months or riding (particularly if I

ride

Quoted message said:

in wet weather) to avoid the two "fusing" together permanently (very
expensive situation since crushing carbon seat post would be the only way
out in such a situation).

Put grease on the carbon post, and it'll glue it to the frame, and then
you won't need a clamp.

Not true. Grease on a seatpost will cause it to need too much clamping force
to hold it in place, which will damage the seatpost. Some carbon frames are
treated with a process that isn't grease-friendly, but it won't cause them
to weld in place as far as I know (nor have I seen this happen due to
grease).

There is a permatex gasket sealer product that can be used as a grease
substitute though. The only reason why you might use it is because grease or
the gasket sealer will help to keep water out of the seat tube.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

"Yuri Budilov" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

I don't know the answers to your questions but I had a carbon Specialized

Roubaix with carbon seat post and their instructions were exactly as the
first reply said - bolt to be on the opposite side to where the
crack/slit/whatever in the seat tube is - to prevent crashing the post. So
I asked my LBS about this rule for Trek Madone and they said that Trek
instructions were to place the bolt on the same side as crack/slit/etc not
on opposite side. This is very puzzling for me too! But I hate to break
Trek warranty by spinning the clamp around 180 degrees. Perhaps someone
can send Trek support an e-mail question? I would if I knew where to send
it to.....

I sent e-mail to Trek Australia yesterday and they said it does not matter
either way and there is no preference on their part re clamp bolt and split
as far as crushing seat post goes....