slipping seatpost solutions

Raymo853 said:

The seatpost on my 2003 Gunnar Rockhound, claims to be a
27.2, always slips. I am considering a new frame to
escape this problem, painful since the frame is fine
otherwise. I bought a Syncros 27.3 seatpost to test, and
it would not fit into the frame so up-sizing is not a
solution. It has done this from day one so it was nothing
I did to the frame.

The amount of slipping has varied based on the seatpost I
am using. A RockShox suspension post was the best, a Titec
carbon next and the Titec AL and current Thompson are the
worse. I had hopes for the Thompson since it has the
external striations and the manufactoring tolerance they
stick to, but it has been pretty bad.

I have used both the stock collar and a salsa lip lock
with no luck. I have tightened the collars to 100% limit
of my physical strength, and past the limit of some of my
allen keys with out any success. I weigh only 155 and this
happens all the time regardless of the terrain, even when
riding on smooth pavement. You can also spin the seat
pretty easily.

Anyone have any ideas on stopping this? I thought about
putting fine sand into the grease or using mylar sheets as
size adjusters. The only problem I am not wild about sand
in the frame and I like to move my seatpost up and down at
times for terrain changes so I am not sure the sheets will
work correctly.

Gunnars are kind of famous for this issues, both the
current crop using 27.2 post and the past crop using 27.0.

Is the slot in the seat tube closing up completely? If so,
can you file it out a bit?

Raymo853' () said:

The seatpost on my 2003 Gunnar Rockhound, claims to be a
27.2, always slips. I am considering a new frame to
escape this problem, painful since the frame is fine
otherwise. I bought a Syncros 27.3 seatpost to test, and
it would not fit into the frame so up-sizing is not a
solution. It has done this from day one so it was nothing
I did to the frame.

I just had a similar problem, using an different post and
styled seat.

I just wrapped some duct tape around the post a couple of
times. and it's been ok so far.

steve

Raymo853 said:

The seatpost on my 2003 Gunnar Rockhound, claims to be a
27.2, always slips. I am considering a new frame to escape
this problem, painful since the frame is fine otherwise. I
bought a Syncros 27.3 seatpost to test, and it would not
fit into the frame so up-sizing is not a solution. It has
done this from day one so it was nothing I did to the
frame. ...

Quoted message said:

Anyone have any ideas on stopping this? I thought about
putting fine sand into the grease or using mylar sheets as
size adjusters. The only problem I am not wild about sand
in the frame and I like to move my seatpost up and down at
times for terrain changes so I am not sure the sheets will
work correctly.

I have used shims cut from aluminum pop/beer cans to stop
slipping seatposts. It does work. If the fit is close the
shim will not have to go all the way around. It may be a
nuisance to keep the shim in place if you adjust seat
height a lot.

Other more professional options are to get a seatpost
knurled or to get a shop or framebuilder to ream or hone
the seat tube to a known size, like 27.4, and use a stock
27.4 seatpost. Are you sure the Syncros post wasn't 27.4mm?
I never heard of a 27.3 mm post. Aluminum seatposts can
also be sanded down slightly to improve a just barely too-
tight fit. Anyway it should be fixable without needing a
new frame.

On Tue, 20 Apr 2004 15:39:23 -0400, "Raymo853" <[email hidden]>

may have said:

The seatpost on my 2003 Gunnar Rockhound, claims to be a
27.2, always slips. I am considering a new frame to
escape this problem, painful since the frame is fine
otherwise. I bought a Syncros 27.3 seatpost to test, and
it would not fit into the frame so up-sizing is not a
solution. It has done this from day one so it was nothing
I did to the frame.

Remove the seatpost and clamp, and look at the slit in the
frame tube. There's probably a tab near the top of the slit
which is keeping the clamp from pinching the tube together
properly. If that's the case, filing the tab out will solve
the problem. Also, position the clamp so that the opening of
it is lined up with the slit in the tube.

If there isn't a slit, or if the slit is less than 15mm in
length, you may need to make one. I've found that 25mm of
slit is almost always adequate even with thick aluminum
tubing, and a shorter slit may still work with thinwall Cr-
Mo tubing. Try to avoid leaving sharp edges or corners, and
your setpost won't get scarred as badly.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

"Raymo853" asked about the slipping seatpost:

<< Anyone have any ideas on stopping this? >>

Fold up a little bit of that very lightweight foil-like
candy wrapper and cram it between the post and the inside of
the frame as you lower the post into the seat tube. That
will stop it.

Robert

Quoted message said:

Quoted message said:

The seatpost on my 2003 Gunnar Rockhound, claims to be a
27.2, always

slips.

Quoted message said:

I am considering a new frame to escape this problem,
painful since the

frame

Quoted message said:

is fine otherwise. I bought a Syncros 27.3 seatpost to
test, and it would not fit into the frame so up-sizing is
not a solution. It has done this from day one so it was
nothing I did to the frame.

Have a shop run a 27.2 reamer through it. You may just be
clamping the post in a couple of places. Phil Brown

Quoted message said:

The seatpost on my 2003 Gunnar Rockhound, claims to be a
27.2, always slips. I am considering a new frame to escape
this problem, painful since the frame is fine otherwise. I
bought a Syncros
27.3 seatpost to test, and it would not fit into the frame
so up-sizing is not a solution.

I had a similar problem with my old Montague. Turned out the
factory-provided seatpost *was* too small, which I deduced
after carefully measuring the seat tube outside diameter and
wall thickness at several points. Fitting a 0.4mm-larger
seatpost was the cure, but involved a good bit of work,
because several months of tightening and re-tightening the
clamp had deformed the top of the seat tube, and the larger-
diameter seatpost wouldn't go in. I restored the sizing and
roundness of the seat tube by forcefully rotating a short
length of water-pipe inside it, using an automotive half-inch-
drive "breaker bar" as a lever: the handle end of the breaker-
bar went inside the pipe, which went inside the seat tube,
with a small [maybe 2mm] clearance between each, enough for
me to rotate 'round while wrestling with the frame to keep
it still. Crude, but effective: the new, larger seatpost
glides up & down just as intended.

"Phil Brown" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Have a shop run a 27.2 reamer through it. You may just be
clamping the

post in

Quoted message said:

a couple of places. Phil Brown

Won't that make it bigger and slip even more? Actually I am
assuming a 27.2 reamer would end up not even touching the
interior of the seat tube.

"You may just be clamping the post in a couple of places."
What does that mean?

"Benjamin Weiner" <[email hidden]> wrote in message
news:4085a2eb$1@darkstar...

Quoted message said:

Other more professional options are to get a seatpost
knurled or to get a shop or framebuilder to ream or hone
the seat tube to a known size, like 27.4, and use a stock
27.4 seatpost. Are you sure the Syncros post wasn't
27.4mm? I never heard of a 27.3 mm post. Aluminum
seatposts can also be sanded down slightly to improve a
just barely too-tight fit. Anyway it should be fixable
without needing a new frame.

I am 100% sure it was a 27.3. It was made for those few
Waterfords that used 27.3 seatposts.

I am not going to do the reaming. I do not like this frame
enough to put money into having it reamed, I would rather go
get a quality frame like an IF instead.

rcc-<< The seatpost on my 2003 Gunnar Rockhound, claims to
be a 27.2, always slips. I am considering a new frame to
escape this problem, painful since the frame is fine
otherwise. >><BR><BR>

Have a competent LBS 'knurl' the seatpost where it goes into
the frameset or have same competent LBS slightly rear the
seatube to accomodate a larger seatpost...no need to get rid
of the frameset.

rcc-<< Gunnars are kind of famous for this issues, both the
current crop using
27.2 post and the past crop using 27.0. >><BR><BR>

Waterford products have been kind of 'famous' for this
for years.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St.
Boulder, CO, 80302
(28)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali
costruite eccezionalmente bene"

Quoted message said:

"Benjamin Weiner" <[email hidden]> wrote in message
news:4085a2eb$1@darkstar...

Quoted message said:

Other more professional options are to get a seatpost
knurled or to get a shop or framebuilder to ream or hone
the seat tube to a known size, like 27.4, and use a stock
27.4 seatpost. Are you sure the Syncros post wasn't
27.4mm? I never heard of a 27.3 mm post. Aluminum
seatposts can also be sanded down slightly to improve a
just barely too-tight fit. Anyway it should be fixable
without needing a new frame.

Raymo853 said:

I am 100% sure it was a 27.3. It was made for those few
Waterfords that used 27.3 seatposts.

I am not going to do the reaming. I do not like this frame
enough to put money into having it reamed, I would rather
go get a quality frame like an IF instead.

That cost is minimal. Also, seatposts vary quite a bit
(which you can see at any bike shop if you bring a
micrometer).

It may indeed be not round but more likely an undersized or
mismarked post. A post may be knurled, BTW, saving even the
cost of a post, so yet another reason to consult a good
frame service shop.

And Waterford ran 27.4, as did a few top-end Italian bikes,
but not 27.3.

Why the gratuitous slam? Both IF and Waterford are at the
pinnacle of our industry.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971