I need help with stuck seat post



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Ken Pisichko

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I just subscribed to this NG after a lot of head scratching over a stuck seat post.

A couple of years I got two "mountain bikes" for my boys. They have grown since last year and now
the seat post is too low for one of them.

The seat post is made of some steel alloy and is coated with some black "paint". I sprayed WD-40 on
the post and frame (tube entry for the post) and tried several times to use the seat as a lever to
turn the post - no deal.

This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to expand
faster than the seat post and thus "release the bond". Didn't work (obviously). I then found and
read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a hair drier or
propane hand torch. Will it wreck the paint? I think it will.

Other suggestions (preferably non-destructive)? Thanks in advance for any help.

Ken
 
Waitaminute- you read Sheldon Brown's 15 suggestions and none of them worked?

Ken Pisichko wrote:

> I just subscribed to this NG after a lot of head scratching over a stuck seat post.
>
> A couple of years I got two "mountain bikes" for my boys. They have grown since last year and now
> the seat post is too low for one of them.
>
> The seat post is made of some steel alloy and is coated with some black "paint". I sprayed WD-40
> on the post and frame (tube entry for the post) and tried several times to use the seat as a lever
> to turn the post - no deal.
>
> This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
> expand faster than the seat post and thus "release the bond". Didn't work (obviously). I then
> found and read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a
> hair drier or propane hand torch. Will it wreck the paint? I think it will.
>
> Other suggestions (preferably non-destructive)? Thanks in advance for any help.
>
> Ken
 
None of the non-destructive methods worked. More WD-40 and this evening heat (aka boiling water
poured on the outside of the frame tube) again. Tring to trist the seat (attached to the seat post)
just results in nothing.

I did not try Sheldon's destructive methods - yet. I posted this plea to this NG because I did not
want to get to the destructive stage.

I just might yet strip much of the frame and put it into the food freezer for a few hours and then
pour boiling H2O in the frame again to see if that works....

Gary Smiley wrote:

> Waitaminute- you read Sheldon Brown's 15 suggestions and none of them worked?
>
> Ken Pisichko wrote:
>
> > I just subscribed to this NG after a lot of head scratching over a stuck seat post.
> >
> > A couple of years I got two "mountain bikes" for my boys. They have grown since last year and
> > now the seat post is too low for one of them.
> >
> > The seat post is made of some steel alloy and is coated with some black "paint". I sprayed WD-40
> > on the post and frame (tube entry for the post) and tried several times to use the seat as a
> > lever to turn the post - no deal.
> >
> > This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
> > expand faster than the seat post and thus "release the bond". Didn't work (obviously). I then
> > found and read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a
> > hair drier or propane hand torch. Will it wreck the paint? I think it will.
> >
> > Other suggestions (preferably non-destructive)? Thanks in advance for any help.
> >
> > Ken
 
I don't know what Sheldon's 15 suggestions are, but I think you might try actually pounding the post
down with a rubber mallet, on the seat (if not to expensive) or take it off and on the post. Might
be able to Jiggle it loose. It works for car parts etc. IMHO.

david

"Ken Pisichko" <[email protected]> wrote in message news:[email protected]...
> I just subscribed to this NG after a lot of head scratching over a
stuck
> seat post.
>
> A couple of years I got two "mountain bikes" for my boys. They have grown since last year and now
> the seat post is too low for one of
them.
>
> The seat post is made of some steel alloy and is coated with some
black
> "paint". I sprayed WD-40 on the post and frame (tube entry for the
post)
> and tried several times to use the seat as a lever to turn the
post - no
> deal.
>
> This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
> expand faster than the seat post and
thus
> "release the bond". Didn't work (obviously). I then found and read Sheldon Brown's 15 suggestions
> (www.harriscyclery.com) but wonder
about
> using a hair drier or propane hand torch. Will it wreck the paint? I think it will.
>
> Other suggestions (preferably non-destructive)? Thanks in advance
for
> any help.
>
> Ken
 
On Sat, 21 Jun 2003 19:23:02 -0400, "david" <[email protected]> wrote:

>I don't know what Sheldon's 15 suggestions are, but I think you might try actually pounding the
>post down with a rubber mallet, on the seat (if not to expensive) or take it off and on the post.
>Might be able to Jiggle it loose. It works for car parts etc. IMHO.

*DON'T* take off the seat and then pound on the post with a mallet. If your luck runs out, it'll
come loose and fall down too far.

Jasper
 
On Sat, 21 Jun 2003 12:35:44 -0500, Ken Pisichko <[email protected]> wrote:

>I just subscribed to this NG after a lot of head scratching over a stuck seat post.
>
>A couple of years I got two "mountain bikes" for my boys. They have grown since last year and now
>the seat post is too low for one of them.
>
>The seat post is made of some steel alloy and is coated with some black "paint". I sprayed WD-40 on
>the post and frame (tube entry for the post) and tried several times to use the seat as a lever to
>turn the post - no deal.
>
>This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
>expand faster than the seat post and thus "release the bond". Didn't work (obviously). I then found
>and read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a hair drier
>or propane hand torch. Will it wreck the paint? I think it will.
>
>Other suggestions (preferably non-destructive)? Thanks in advance for any help.
>
>Ken

When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter become
larger? My gut instinct says that the inside diameter would become smaller with expansion while the
outside diameter increases. I don't know what really happens.

Also, if the post and frame are both steel, possibly similar alloys, again my gut instinct is
that heat will make things worse as they problem diameters- outer post and inner frame- will
expand together.

You tried removing the seat, flipping the bike over and grabbing the post in a bench vice, and
twisting the frame away from the post? Use the main triangle, not the rear triangle, for twisting.
You can use a 2x4 to leverage, between the head tube and seat tube, but you can also bend the frame
if the seat post doesn't let go and you apply too much pressure.

Also try removing the bottom bracket and spary/drip Liquid Wrench from the access hole which
hopefully exists in the BB shell. Flip the bike over when you do this. The idea is to get the
lubricant to flow between the post and frame at the bottom of the post. If you can get lubricant in
there, let it sit for a while.

But wait- if the seat post is frozen, you might find the bottom bracket also frozen.....
 
Dan Daniel wrote:

> When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter become
> larger? My gut instinct says that the inside diameter would become smaller with expansion while
> the outside diameter increases. I don't know what really happens.

If the material is heated uniformly then it will expand in size without any change in shape - same
as if you took a photo and enlarged it. So the size of the hole increases in the same ratio as the
outer circle. One way to see this is to consider the case where you have a tube and a rod that just
fits inside, both made of the same material. Put the rod inside; heat the whole material uniformly;
and then remove the rod. The rod will have a larger diameter than originally so the hole in the tube
must as well.
 
Peter wrote:

> Dan Daniel wrote:
>
> > When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter
> > become larger? My gut instinct says that the inside diameter would become smaller with expansion
> > while the outside diameter increases. I don't know what really happens.
>
> If the material is heated uniformly then it will expand in size without any change in shape - same
> as if you took a photo and enlarged it. So the size of the hole increases in the same ratio as the
> outer circle. One way to see this is to consider the case where you have a tube and a rod that
> just fits inside, both made of the same material. Put the rod inside; heat the whole material
> uniformly; and then remove the rod. The rod will have a larger diameter than originally so the
> hole in the tube must as well.

This is precisely what is done when a new starter gear is put on a car's flywheel. On my '72 Land
Rover for instance, the factory manual states to put the gear in the oven and have the temp set at
??? degrees F. There is a time to wait while the gear heats and expands. Then the wheel is taken out
of the oven and placed over the gear-less flywheel. Careful alignment to make sure it is even all
round and the gear cools and firmly clamps itself to the flywheel. Naturally this is done with metal
working tongs and leather/heat proof gloves.

This is irreversible for if you have the gear on ****-eyed you have to drill a hole in it's
circumference and use a cold chisel to break the gear in half. No problem - just buy another one!
 
One question only: did you unloosen the crew?

:)

--
~~~~~~~~~~~~~~~~~~
Martin Borsje Geleen Netherlands

"Ken Pisichko" <[email protected]> wrote in message news:[email protected]...
> I just subscribed to this NG after a lot of head scratching over a stuck seat post.
>
> A couple of years I got two "mountain bikes" for my boys. They have grown since last year and now
> the seat post is too low for one of them.
>
> The seat post is made of some steel alloy and is coated with some black "paint". I sprayed WD-40
> on the post and frame (tube entry for the post) and tried several times to use the seat as a lever
> to turn the post - no deal.
>
> This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
> expand faster than the seat post and thus "release the bond". Didn't work (obviously). I then
> found and read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a
> hair drier or propane hand torch. Will it wreck the paint? I think it will.
>
> Other suggestions (preferably non-destructive)? Thanks in advance for any help.
>
> Ken
 
Yes, I did not forget the obvious - I did remove the bolt-cross screw entirely, and even tried
to pry the "ears" of the clamp apart a little bit. Sometimes the obvious is ignored, but not
this time. :)

Ken Canada

Martin Borsje wrote:

> One question only: did you unloosen the crew?
>
> :)
>
> --
> ~~~~~~~~~~~~~~~~~~
> Martin Borsje Geleen Netherlands
>
> "Ken Pisichko" <[email protected]> wrote in message news:[email protected]...
> > I just subscribed to this NG after a lot of head scratching over a stuck seat post.
> >
> > A couple of years I got two "mountain bikes" for my boys. They have grown since last year and
> > now the seat post is too low for one of them.
> >
> > The seat post is made of some steel alloy and is coated with some black "paint". I sprayed WD-40
> > on the post and frame (tube entry for the post) and tried several times to use the seat as a
> > lever to turn the post - no deal.
> >
> > This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
> > expand faster than the seat post and thus "release the bond". Didn't work (obviously). I then
> > found and read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a
> > hair drier or propane hand torch. Will it wreck the paint? I think it will.
> >
> > Other suggestions (preferably non-destructive)? Thanks in advance for any help.
> >
> > Ken
 
On Sat, 21 Jun 2003 17:07:39 -0500, Ken Pisichko <[email protected]> wrote:

>None of the non-destructive methods worked. More WD-40 and this evening heat (aka boiling water
>poured on the outside of the frame tube) again. Tring to trist the seat (attached to the seat post)
>just results in nothing.
>
>I did not try Sheldon's destructive methods - yet. I posted this plea to this NG because I did not
>want to get to the destructive stage.
>
>I just might yet strip much of the frame and put it into the food freezer for a few hours and then
>pour boiling H2O in the frame again to see if that works....
>

Jumping the gun a bit here, but if you do get it free (hope you do!) then remember to give it a good
clean and *grease* the stem before resetting the height. As you're discovering now, very important!

I remember buying a 531 road bike from the auction a few months ago which had a stuck seat stem
(although this one was an aluminium stem). I tried everything, absolutely everything. I even got to
the 'destructive' phase and still couldn't budge the damn thing. In the end I managed to ruin the
frame - spliting it at the top of the seat stay. By this time I was down to monkey wrench with a
large extension lever!!!!

Have you tried heating it, and then cooling it quickly with cold water? You want that heat to
'break' a seal that may have formed. If you can heat it that much (without ruining paint ...not
easy) it must help.

Good luck.

Garry

>Gary Smiley wrote:
>
>> Waitaminute- you read Sheldon Brown's 15 suggestions and none of them worked?
>>
>> Ken Pisichko wrote:
>>
>> > I just subscribed to this NG after a lot of head scratching over a stuck seat post.
>> >
>> > A couple of years I got two "mountain bikes" for my boys. They have grown since last year and
>> > now the seat post is too low for one of them.
>> >
>> > The seat post is made of some steel alloy and is coated with some black "paint". I sprayed
>> > WD-40 on the post and frame (tube entry for the post) and tried several times to use the seat
>> > as a lever to turn the post - no deal.
>> >
>> > This AM I got a brain wave to heat the frame tube with hot water, expecting the frame tube to
>> > expand faster than the seat post and thus "release the bond". Didn't work (obviously). I then
>> > found and read Sheldon Brown's 15 suggestions (www.harriscyclery.com) but wonder about using a
>> > hair drier or propane hand torch. Will it wreck the paint? I think it will.
>> >
>> > Other suggestions (preferably non-destructive)? Thanks in advance for any help.
>> >
>> > Ken
 
Dan Daniel asked:

>>>When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter
>>>become larger? My gut instinct says that the inside diameter would become smaller with expansion
>>>while the outside diameter increases. I don't know what really happens.

"Peter" replied

>>If the material is heated uniformly then it will expand in size without any change in shape - same
>>as if you took a photo and enlarged it. So the size of the hole increases in the same ratio as the
>>outer circle. One way to see this is to consider the case where you have a tube and a rod that
>>just fits inside, both made of the same material. Put the rod inside; heat the whole material
>>uniformly; and then remove the rod. The rod will have a larger diameter than originally so the
>>hole in the tube must as well.

Ken Pisichko added:

> This is precisely what is done when a new starter gear is put on a car's flywheel. On my '72 Land
> Rover for instance, the factory manual states to put the gear in the oven and have the temp set at
> ??? degrees F. There is a time to wait while the gear heats and expands. Then the wheel is taken
> out of the oven and placed over the gear-less flywheel. Careful alignment to make sure it is even
> all round and the gear cools and firmly clamps itself to the flywheel.

This is all true, but only if the seatpost and frame are made out of the same metal.

In the very common case of an aluminum seatpost stuck in a steel frame, however, this is
counterproductive, because aluminum expands twice as much as steel when heated. For this
combination, chilling is often the ultimate weapon. I've done this with dry ice and with
liquid nitrogen.

See also http://sheldonbrown.com/stuck-seatposts.html

Sheldon "Hot & Cold" Brown +-----------------------------------------------+
| A government that robs Peter to pay Paul | can always depend upon the support of Paul. | --George
| Bernard Shaw |
+-----------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
 
really wasn't the seatpost the "unloose" part? and the binder bolt was allready untightened?

PS "someone" appears to have been european and his usage could be forgiven... Oh wait we just had a
thread condemming those who speak other languages poorly..... my bad

Sheldon Brown wrote:

> Someone asked:
>
>> One question only: did you unloosen the crew?
>
>
> No need, the screw was already unloose.
>
> Carapace Completed Umber
>
> http://sheldonbrown.com/stuck-seatposts.html
 
>In the very common case of an aluminum seatpost stuck in a steel frame, however, this is
>counterproductive, because aluminum expands twice as much as steel when heated. For this
>combination, chilling is often the ultimate weapon. I've done this with dry ice and with liquid
>nitrogen.
>
>See also http://sheldonbrown.com/stuck-seatposts.html

Small disposable pipe feezing cannisters that plumbers use to freeze a water pipe come to mind here.
Might be worth a shot.

Garry
 
On Sun, 22 Jun 2003 18:00:37 GMT, Sheldon Brown <[email protected]> wrote:

>In the very common case of an aluminum seatpost stuck in a steel frame, however, this is
>counterproductive, because aluminum expands twice as much as steel when heated. For this
>combination, chilling is often the ultimate weapon. I've done this with dry ice and with liquid
>nitrogen.

Wouldn't it help to raise the temperature (say to 100C, boiling water) first? Either the aluminium
or the steel should deform a little, because if it's already stuck, it can't expand further unless
the diameter of the seatpost decreases or the frame tube increases, (corrected for temperature).
But.. hmm.. wait. If you have a butted seat tube or the even more common metal collar around the
top, then it might be that the difference in response at the top and in the middle could lead to the
deeper part becoming wedged even tighter, by actually being a wedge.

Ok, not so hot an idea.

Jasper
 
>One question only: did you unloosen the screw?
>
>:)
>--
>~~~~~~~~~~~~~~~~~~
>Martin Borsje Geleen Netherlands

"UN-loosen"? That would mean tighten it! Wouldn't that defeat the entire purpose?

May you have the wind at your back. And a really low gear for the hills! Chris

Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
 
On Sat, 21 Jun 2003 20:01:57 +0000, Dan Daniel wrote:

> When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter
> become larger?

es, it does. That is why this technique sometimes works.

> My gut instinct says that the inside diameter would become smaller with expansion while the
> outside diameter increases. I don't know what really happens.

You're thinking that the tube will swell and get thicker. But expansion under heat is in all
directions, including the radius of the tube.

But this tube is glued to the post with rust, it seems.

--

David L. Johnson

__o | A foolish consistency is the hobgoblin of little minds, adored _`\(,_ | by little statesmen
and philosophers and divines. --Ralph Waldo (_)/ (_) | Emerson
 
On Sun, 22 Jun 2003 03:31:14 GMT, Peter <[email protected]> wrote:

>Dan Daniel wrote:
>
>> When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter
>> become larger? My gut instinct says that the inside diameter would become smaller with expansion
>> while the outside diameter increases. I don't know what really happens.
>
>If the material is heated uniformly then it will expand in size without any change in shape - same
>as if you took a photo and enlarged it. So the size of the hole increases in the same ratio as the
>outer circle. One way to see this is to consider the case where you have a tube and a rod that just
>fits inside, both made of the same material. Put the rod inside; heat the whole material uniformly;
>and then remove the rod. The rod will have a larger diameter than originally so the hole in the
>tube must as well.

Thanks for the clarification. It makes sense now. For some reason I was picturing it almost like a
ring of bacteria growing, which will go in all directions. But it's more like a series of
concentric circles of bricks where each brick gets bigger as heated (or the mortar joints/distance
between bricks grows). No way for a molecule/brick to expand and occupy *less* space as I was
mistakenly thinking.
 
On Sun, 22 Jun 2003 18:24:28 -0400, "David L. Johnson" <[email protected]> wrote:

>On Sat, 21 Jun 2003 20:01:57 +0000, Dan Daniel wrote:
>
>> When a tube is heated and expands, does it only expand 'outwards'? Does the inside diameter
>> become larger?
>
>es, it does. That is why this technique sometimes works.
>
>> My gut instinct says that the inside diameter would become smaller with expansion while the
>> outside diameter increases. I don't know what really happens.
>
>You're thinking that the tube will swell and get thicker. But expansion under heat is in all
>directions, including the radius of the tube.
>

Ok, it's sinking in. Thanks.

Your phrasing itself points to my own confusion. '...in all directions' makes me think of expanding
towards the tube's center as well as away from it. If, say, the tube's center is 0,0 on an X-Y grid,
and the inside of the tube starts at 5 units away from 0,0, the tube never does 'expand' towards
0,0, which is certainly part of 'all directions.'

>But this tube is glued to the post with rust, it seems.

Yep. I guess that the heating is an attempt to physically create distance between the two surfaces
in the hope that the rust will break away from one or the other.
 
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