Slipping carbon seatpost on a Roubaix

A beer can shim solution would be poetic.

Phil said:

So a customer comes in on his spendy newish S-Works Roubaix. He has
had the chronic seatpost slipping problem that occurs with smooth
carbon seat tubes and seatposts. He has already roughened up the
surface of the seatpost a little bit, and that didn't help. It still
slips over the progress of an entire ride.

The problem is the loose fit of the seatpost/seat tube. When the
seatpost is inserted a good 5 inches, it wiggles very slightly,
something that shouldn't occur even when inserted 2 inches. The
seatpost is a Specialized S-Works seatpost. I didn't get the chance
to measure the ID/OD of the system to see which one was out of spec,
but I'm hoping it's the seatpost, obviously. More sanding I don't
think is an option, as it removes material when adding material is
the objective.
What do you all suggest about fixing this problem? I'll measure it
next time he comes back, but if the seatpost is a 27.2, it shouldn't
have a clearance fit at all... it should be exactly 27.2, right? The
seat tube should be the one slightly large, like 27.28 or thereabouts.

A Deda Blackstik (?) slipped some in my carbon frame, so I wrapped a little
plumber's tape around it. Been holding fine ever since (the binder is
/tight/, however).

Bill "now if it weren't for those dern microadjust tilt teeth things" S.

Sorni said:

Phil said:

So a customer comes in on his spendy newish S-Works Roubaix. He has
had the chronic seatpost slipping problem that occurs with smooth
carbon seat tubes and seatposts. He has already roughened up the
surface of the seatpost a little bit, and that didn't help. It still
slips over the progress of an entire ride.

The problem is the loose fit of the seatpost/seat tube. When the
seatpost is inserted a good 5 inches, it wiggles very slightly,
something that shouldn't occur even when inserted 2 inches. The
seatpost is a Specialized S-Works seatpost. I didn't get the chance
to measure the ID/OD of the system to see which one was out of spec,
but I'm hoping it's the seatpost, obviously. More sanding I don't
think is an option, as it removes material when adding material is
the objective.
What do you all suggest about fixing this problem? I'll measure it
next time he comes back, but if the seatpost is a 27.2, it shouldn't
have a clearance fit at all... it should be exactly 27.2, right? The
seat tube should be the one slightly large, like 27.28 or
thereabouts.

A Deda Blackstik (?) slipped some in my carbon frame, so I wrapped a
little plumber's tape around it. Been holding fine ever since (the
binder is /tight/, however).

Bill "now if it weren't for those dern microadjust tilt teeth things"
S.

Erh? You mean the thickness of the tape was thin enough to fit in the seat
tube?

--
Phil

Phil said:

Sorni said:

Phil said:

So a customer comes in on his spendy newish S-Works Roubaix. He has
had the chronic seatpost slipping problem that occurs with smooth
carbon seat tubes and seatposts. He has already roughened up the
surface of the seatpost a little bit, and that didn't help. It
still slips over the progress of an entire ride.

The problem is the loose fit of the seatpost/seat tube. When the
seatpost is inserted a good 5 inches, it wiggles very slightly,
something that shouldn't occur even when inserted 2 inches. The
seatpost is a Specialized S-Works seatpost. I didn't get the chance
to measure the ID/OD of the system to see which one was out of spec,
but I'm hoping it's the seatpost, obviously. More sanding I don't
think is an option, as it removes material when adding material is
the objective.
What do you all suggest about fixing this problem? I'll measure it
next time he comes back, but if the seatpost is a 27.2, it shouldn't
have a clearance fit at all... it should be exactly 27.2, right? The
seat tube should be the one slightly large, like 27.28 or
thereabouts.

A Deda Blackstik (?) slipped some in my carbon frame, so I wrapped a
little plumber's tape around it. Been holding fine ever since (the
binder is /tight/, however).

Bill "now if it weren't for those dern microadjust tilt teeth things"
S.

Erh? You mean the thickness of the tape was thin enough to fit in
the seat tube?

IIRC, I put a little electrical tape lower on the post -- mostly for the
"sticky factor" as it mangled (I assumed) -- then a wrap of the thin white
stuff just below frame level. With careful insertion (yeah, yeah), I got
some of it inside the seat tube and then it bunched up, giving just enough
added girth (?) to make the binder hold. (Also provides a nice ugly post
level demarcation.)

What about spraying the post with hair spray -- letting it get really
tacky -- and then installing? Only temporary?

Bill "wonder why no one lets me near their bikes with tools?" S.

Phil said:

So a customer comes in on his spendy newish S-Works Roubaix. He has had the
chronic seatpost slipping problem that occurs with smooth carbon seat tubes
and seatposts. He has already roughened up the surface of the seatpost a
little bit, and that didn't help. It still slips over the progress of an
entire ride.

The problem is the loose fit of the seatpost/seat tube. When the seatpost
is inserted a good 5 inches, it wiggles very slightly, something that
shouldn't occur even when inserted 2 inches. The seatpost is a Specialized
S-Works seatpost. I didn't get the chance to measure the ID/OD of the
system to see which one was out of spec, but I'm hoping it's the seatpost,
obviously. More sanding I don't think is an option, as it removes material
when adding material is the objective.

What do you all suggest about fixing this problem? I'll measure it next
time he comes back, but if the seatpost is a 27.2, it shouldn't have a
clearance fit at all... it should be exactly 27.2, right? The seat tube
should be the one slightly large, like 27.28 or thereabouts.

--
Phil

I have seen Tacx carbon-paste used in similar situations.

Joseph

"Phil, Squid-in-Training" <[email hidden]> schreef in
bericht news:vrwbg.13130$8q.1231@dukeread08...

Quoted message said:

So a customer comes in on his spendy newish S-Works Roubaix. He has had

the

Quoted message said:

chronic seatpost slipping problem that occurs with smooth carbon seat

tubes

Quoted message said:

and seatposts. He has already roughened up the surface of the seatpost a
little bit, and that didn't help. It still slips over the progress of an
entire ride.

The problem is the loose fit of the seatpost/seat tube. When the seatpost
is inserted a good 5 inches, it wiggles very slightly, something that
shouldn't occur even when inserted 2 inches. The seatpost is a

Specialized

Quoted message said:

S-Works seatpost. I didn't get the chance to measure the ID/OD of the
system to see which one was out of spec, but I'm hoping it's the seatpost,
obviously. More sanding I don't think is an option, as it removes

material

Quoted message said:

when adding material is the objective.

What do you all suggest about fixing this problem? I'll measure it next
time he comes back, but if the seatpost is a 27.2, it shouldn't have a
clearance fit at all... it should be exactly 27.2, right? The seat tube
should be the one slightly large, like 27.28 or thereabouts.

--
Phil

I think you definitely should use the right size of seatpost in the first
place. Besides of that I had the problem of slipping as well. In an English
bikemagazin I red a testreport of a Giant TCR with carbon seatpost which
slips in the test and the next tip:

Put a little hairspray on the seatpost. Just blow to let it dry a little
and put it in. It makes the seatpost very "nonslippery".

To keep all the dirt out I sealed the seams with a very little of
silliconkit. It works for two years now.

Succes

Why not contact Specialized? They have offices in Morgan Hill Ca and I
think there is an email helpdesk for cycling tech issues. Since both
are Specialized that is the best bet. Most CF (as I understand) does
not specify lube in the seat tube / post interface. I wonder if the
customer had done that when he got it and then ended up taking material
out trying to clean up the mess. After all, the lube would have started
the whole problem and the state you describe is what I would expect to
see after the scenario I indicated. The last possibility is that the
seat tube cluster is defective and or out of spec. The aluminum M4
S-Works from a few years ago had to have the seat post clamp in the
seat tube revised because of a design flaw. There are a lot of unusual
solutions (to clamping the seatpost) in frames these days as the race
to drop weight and look "aero" continues.

I agree that putting something in the gap might work but I would only
do that as a last resort after talking to Specialized and the owner.

Hans said:

"Phil, Squid-in-Training" <[email hidden]>
schreef in bericht news:vrwbg.13130$8q.1231@dukeread08...

Quoted message said:

So a customer comes in on his spendy newish S-Works Roubaix. He has
had the chronic seatpost slipping problem that occurs with smooth
carbon seat tubes and seatposts. He has already roughened up the
surface of the seatpost a little bit, and that didn't help. It
still slips over the progress of an entire ride.

The problem is the loose fit of the seatpost/seat tube. When the
seatpost is inserted a good 5 inches, it wiggles very slightly,
something that shouldn't occur even when inserted 2 inches. The
seatpost is a Specialized S-Works seatpost. I didn't get the chance
to measure the ID/OD of the system to see which one was out of spec,
but I'm hoping it's the seatpost, obviously. More sanding I don't
think is an option, as it removes material when adding material is
the objective.

What do you all suggest about fixing this problem? I'll measure it
next time he comes back, but if the seatpost is a 27.2, it shouldn't
have a clearance fit at all... it should be exactly 27.2, right?
The seat tube should be the one slightly large, like 27.28 or
thereabouts.

--
Phil

I think you definitely should use the right size of seatpost in the
first place.

It is. I'm talking about manufacturing tolerances, not gross diameter
differences.

Quoted message said:

Besides of that I had the problem of slipping as well.
In an English bikemagazin I red a testreport of a Giant TCR with
carbon seatpost which slips in the test and the next tip:

Put a little hairspray on the seatpost. Just blow to let it dry a
little and put it in. It makes the seatpost very "nonslippery".

Any word on what it does to the matrix?

--
Phil

Chris M said:

Why not contact Specialized? They have offices in Morgan Hill Ca and I
think there is an email helpdesk for cycling tech issues. Since both

I would, but I figured there was a quick and easy fix available.

Quoted message said:

are Specialized that is the best bet. Most CF (as I understand) does
not specify lube in the seat tube / post interface. I wonder if the
customer had done that when he got it and then ended up taking
material out trying to clean up the mess. After all, the lube would
have started the whole problem and the state you describe is what I
would expect to see after the scenario I indicated. The last
possibility is that the seat tube cluster is defective and or out of
spec. The aluminum M4 S-Works from a few years ago had to have the
seat post clamp in the seat tube revised because of a design flaw.
There are a lot of unusual solutions (to clamping the seatpost) in
frames these days as the race to drop weight and look "aero"
continues.

I agree that putting something in the gap might work but I would only
do that as a last resort after talking to Specialized and the owner.

This owner wouldn't bugger things up that way. Besides, taking that route
is counter-intuitive. He is careful around it and figured sanding wouldn't
do too much harm.

--
Phil

Phil said:

The problem is the loose fit of the seatpost/seat tube. When the seatpost
is inserted a good 5 inches, it wiggles very slightly, something that
shouldn't occur even when inserted 2 inches. The seatpost is a Specialized
S-Works seatpost. I didn't get the chance to measure the ID/OD of the
system to see which one was out of spec, but I'm hoping it's the seatpost,
obviously. More sanding I don't think is an option, as it removes material
when adding material is the objective.

One thing I like to have handy is Loctite 620 (the bearing retainer).
It does the same job as a shim except it's a liquid that cures into a
solid, but it's not an adsesive like epoxy. I've used it for headset
cups in damaged frames.

"Phil, Squid-in-Training" <[email hidden]> schreef in
bericht news:M3Qbg.13206$8q.13198@dukeread08...

Quoted message said:

Hans said:

"Phil, Squid-in-Training" <[email hidden]>
schreef in bericht news:vrwbg.13130$8q.1231@dukeread08...

Quoted message said:

So a customer comes in on his spendy newish S-Works Roubaix. He has
had the chronic seatpost slipping problem that occurs with smooth
carbon seat tubes and seatposts. He has already roughened up the
surface of the seatpost a little bit, and that didn't help. It
still slips over the progress of an entire ride.

The problem is the loose fit of the seatpost/seat tube. When the
seatpost is inserted a good 5 inches, it wiggles very slightly,
something that shouldn't occur even when inserted 2 inches. The
seatpost is a Specialized S-Works seatpost. I didn't get the chance
to measure the ID/OD of the system to see which one was out of spec,
but I'm hoping it's the seatpost, obviously. More sanding I don't
think is an option, as it removes material when adding material is
the objective.

What do you all suggest about fixing this problem? I'll measure it
next time he comes back, but if the seatpost is a 27.2, it shouldn't
have a clearance fit at all... it should be exactly 27.2, right?
The seat tube should be the one slightly large, like 27.28 or
thereabouts.

--
Phil

I think you definitely should use the right size of seatpost in the
first place.

It is. I'm talking about manufacturing tolerances, not gross diameter
differences.

Quoted message said:

Besides of that I had the problem of slipping as well.
In an English bikemagazin I red a testreport of a Giant TCR with
carbon seatpost which slips in the test and the next tip:

Put a little hairspray on the seatpost. Just blow to let it dry a
little and put it in. It makes the seatpost very "nonslippery".

Any word on what it does to the matrix?

--
Phil

About two years ago I cleaned the seatpost and did not see any consequences
for the matrix. I put on hairspray again and put it in again.

Hans

Phil said:

So a customer comes in on his spendy newish S-Works Roubaix. He has had the
chronic seatpost slipping problem that occurs with smooth carbon seat tubes
and seatposts. He has already roughened up the surface of the seatpost a
little bit, and that didn't help. It still slips over the progress of an
entire ride.

The problem is the loose fit of the seatpost/seat tube. When the seatpost
is inserted a good 5 inches, it wiggles very slightly, something that
shouldn't occur even when inserted 2 inches. The seatpost is a Specialized
S-Works seatpost. I didn't get the chance to measure the ID/OD of the
system to see which one was out of spec, but I'm hoping it's the seatpost,
obviously. More sanding I don't think is an option, as it removes material
when adding material is the objective.

What do you all suggest about fixing this problem? I'll measure it next
time he comes back, but if the seatpost is a 27.2, it shouldn't have a
clearance fit at all... it should be exactly 27.2, right? The seat tube
should be the one slightly large, like 27.28 or thereabouts.

--
Phil

Stainless stell metal band clamp around the seatpost right above the
collar. Saw it on a carbon Orbea frame with carbon post. Seemed to
work, if not look pretty. No permanent damage to anything.

I had this problem too. Specialized recommends (and it works) roughing
seat post up with course sandpaper, and putting some climbers chalk on
tube as well. Works like a champ!

Squid-in-Training said:

So a customer comes in on his spendy newish S-Works Roubaix. He has had the
chronic seatpost slipping problem that occurs with smooth carbon seat tubes
and seatposts. He has already roughened up the surface of the seatpost a
little bit, and that didn't help. It still slips over the progress of an
entire ride.

The problem is the loose fit of the seatpost/seat tube. When the seatpost
is inserted a good 5 inches, it wiggles very slightly, something that
shouldn't occur even when inserted 2 inches. The seatpost is a Specialized
S-Works seatpost. I didn't get the chance to measure the ID/OD of the
system to see which one was out of spec, but I'm hoping it's the seatpost,
obviously. More sanding I don't think is an option, as it removes material
when adding material is the objective.

What do you all suggest about fixing this problem? I'll measure it next
time he comes back, but if the seatpost is a 27.2, it shouldn't have a
clearance fit at all... it should be exactly 27.2, right? The seat tube
should be the one slightly large, like 27.28 or thereabouts.