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Old February 24th 19, 09:52 PM posted to rec.bicycles.misc
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Default help unseizing seatpost!

On Sunday, 24 February 2019 09:15:14 UTC, John B. Slocomb wrote:
On Sun, 24 Feb 2019 00:32:38 -0800 (PST), vinokourovswaterbottle


On Sunday, 24 February 2019 05:05:37 UTC, John B. Slocomb wrote:
On Sun, 24 Feb 2019 11:14:48 +0700, John B. Slocomb

On Sat, 23 Feb 2019 14:31:28 -0800 (PST), vinokourovswaterbottle

looking for your help on this one...

So I have this road bike with carbon fibre frame bought second hand and the seatpost is stubbornly seized inside it.

I have tried spraying generous amounts of normal lubricating oil and penetrating oil from both sides (top and bottom of where the seatpost meets the frame, reached the bottom by removing some screws to gain access to the inside of the frame), this was done several times over the space of a day and even leaving it sink-in overnight...

I have also tried heating the frame pouring hot water as I've seen in some online videos, on top of that, I have also tried heating the frame with a heatgun at a relatively safe temperature (the heatgun has a digital dial to control it).

I have also tried melting silicone on the nose of pliers and grabbing the seatpost with them, there was some grip but not enough to unseize it, the force being applied was so strong that the pliers eventually went through the dried silicone leaving some cosmetic marks on the seat post, so I had to stop to prevent more damage.

Additionally, when I try grabbing and turning the saddle to unseize the seatpost, the saddle railings on the seat rail clamp come off, making it impossible to continue turning unless I put the railings back on the clamps and tighten them; needless to say, no matter how much force I apply, it's always the saddle railings coming off but the seatpost doesn't move a millimetre...

None of it has worked so far, but I don't wanna give up.

I've been reading some literature regarding this matter online and tried to work out the logic of way number 14 on this website ( but I don't quite understand how to do it. It might be the way!

I'm attaching some pictures of the frame and the seatpost with as much detail as I can.

Look forward to your suggestions and help.

ps. cutting off the seatpost is not quite an option at this stage.

It seems that you are being careful when you heat the carbon fiber
frame and I would emphasize that. It might also be noted that as a
general statement carbon fiber has an "extremely low coefficient of
thermal expansion (CTE)" see:
I would also be extremely careful prying or twisting on a carbon
frame. Carbon fiber while quite string in some directions can be
rather weak in others.

Should have read "quite Strong"

You might look at:
See also:

I have used a lye (caustic soda)-water mixture to remove aluminum seat
posts from steel frames but have no idea whether lye effects carbon
fiber. If it doesn't then that is a relatively easy method although
the lye mixture is very caustic and you need to be careful when using
it not to get it on yourself or your clothes.


John B.

Thank you for your suggestion!

Below full bike specs, so you may see the material it's made of and so on:

Would this change anything?

If it were mine and I wanted to use lye the first thing I would do is
research the properties of carbon fiber. It might be that carbon fiber
frames are proof against lye, in which case you could use lye to
destroy the aluminum seat post. Note that lye is not an instant
solution and it might take a day or so for the lye to "eat" the seat

Even it appears that lye is safe to use with carbon I would still take
great pains to first test it on some part of the frame that is not
easily visible. Another point is that carbon frames normally are
coated with some sort of epoxy paint or other covering that might not
react with lye while the inside of the frame may be uncoated carbon

Having said that I also would not attempt resorting to a pipe wrench
or any sort of puller that applies any force to the frame as
composites can be very strong in some directions while being
relatively weak in others.

I think that if it were my bike I would first try the CO2 fire
extinguisher as shown in
as it seems the safest method. But beware CO2 is cold enough to freeze
your hands, feet, etc.

An alternate method might be to use "Freeze spray" a spray that is
sometimes used to trouble shoot electronic problems. This comes in a
spray can and could be used to chill the aluminum post. Again a
warning, this stuff is cold enough to frost bite your body. Do Not
spray it on yourself. See

Having said all that I would also advise addressing a post to Andrew
Muzi, on as he has been the bicycle business for years and
years and can probably advise you better then I can.

Good luck with your endeavors.

John B.

So today I did buy some freezing spray for pipes, it did ice the seatpost but sadly, I couldn't pull it out.

The saddle railings attached to the clamp come off at a certain pressure, which makes me question the overall quality of the thing itself...

After your messages I worked out the frame is not a full carbon fibre frame, which is contradictory to what it reads on the manufacturer's website.

I had already used locking pliers as suggested by one of you, hence the reason of the marks in the seatpost, Also, whilst doing it, I found its surface rather slippery, I didn't get the ideal grip with rubbery materials, this would leave me with the option to go full on "naked" with the pliers and therefore (and most likely) damage the seatpost.

I pretty much appreciate all the messages suggesting chemical solutions to fix this but I object, I don't want to risk damaging the frame (and therefore, leaving my bike unusable), also, some of the chemicals are hard to get hold in the UK and well, I wouldn't really need the big can they usually come in so waste of money.

Needless to say I am trying to keep the cost down to fix this, thankfully most of your suggestions are within reasonable cost.

If anyone can suggest a good replacement seatpost under GBP20,00/USD30,00 for sale at, I will probably remove the current one by force using locking pliers or cutting it off.

Many thanks once again for all of your help!

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