Removing stuck seatpost

brit66

Yes, it's carbon and yes, has been in same position for years.

I tried the hot/cold water method to try to expand/contract the aluminium frame, but no luck. Although admittedly it was a pretty half-hearted attempt.

I was thinking of trying penetrating oil but am skeptical this will ever reach down the full length of the seatpost inside the frame downtube.

Anyone got any ideas?

Thanks.

Nick Payne

Have a look at some of the suggestions here: http://www.parktool.com/blog/repair-help/seized-seatposts-and-stems

or here: http://velonews.competitor.com/2009/10/news/road/stuck_seatpost_99640

joe2008

I've just removed a stuck aluminium post from a carbon frame by cutting horizontally across, then two cuts down the seatpost, break the post and pull out.

Probably be easier with a carbon post: the post will be easier to cut and you don't have to worry about cutting into a carbon frame.

step83

If you go down the pentrating fluid route, take the BB out youll likely find theres a hole where the tube goes, squirt penetrating oil down the sides of that tube an leave it overnight, youll know if its worked youll have fluid that will have ran out the seat post. Mentioned in the Velonews link Nick posted, done that with a few stuck seatposts usually does the trick.

Also dont know what your using but a good penetrating fluid is a must WD40 isnt cut out for it.

brit66

Thanks for all the suggestions.

I think I will try the penetrating oil option first as it's the cheapest option. However I can't add the oil from the BB as well because the BB has a sleeve around it.

If it needs cutting I think I will take it to my LBC as I'm not confident I won't screw it up. I also noticed in one of the links provided that someone doesn't recommend cutting carbon - but I assume this is because of the nature of the material (i.e. danger of splinters) rather than anything else.

keef66

It's recommended that you don't inhale the dust, but carbon's surprisingly easy to saw through.

Don't think that penetrating oil will make much difference to a carbon post stuck in an alloy frame or vice versa. It's the aluminium corrosion that expands to fill any voids between the two materials and makes removal extremely difficult.

I have both combinations; alu post in the carbon framed bike and carbon post in the alu framed one. I remove them at least every 6 months for a quick wipe and reapplication of a bit of carbon assembly paste. This has the dual benefits of deterring corrosion, and making them much less susceptible to slipping.

brit66

It's recommended that you don't inhale the dust, but carbon's surprisingly easy to saw through.

Don't think that penetrating oil will make much difference to a carbon post stuck in an alloy frame or vice versa. It's the aluminium corrosion that expands to fill any voids between the two materials and makes removal extremely difficult.

I have both combinations; alu post in the carbon framed bike and carbon post in the alu framed one. I remove them at least every 6 months for a quick wipe and reapplication of a bit of carbon assembly paste. This has the dual benefits of deterring corrosion, and making them much less susceptible to slipping.

With hindsight I would have removed the post as well from time-to-time. I will do this with my new bike.

I only want to raise the saddle by say, a centimeter

N0bodyOfTheGoat

~20 years ago I removed a stuck seatpost inside my old Peugeot 531 frame by turning the bike upside down and pouring most of a can of coke into the hole on the underside of the seat tube. Left it for >24 hours, then turned bike right way up again, gently hit the saddle further into the tube with a mallet and piece of wood to loosen the post and then it came out easily.

6wheels

Pour your penetrating oil of choice through the seat tube bottle cage threaded hole.

lpretro1

The Seatpost Man: http://www.theseatpostman.com/
will get it out no problem - not cheap but better than having to buy a new frame. He's removed a few for our customers and never failed even when they have been quite bad

brit66

Pour your penetrating oil of choice through the seat tube bottle cage threaded hole.

Thanks. I'll try this.

The Seatpost Man: http://www.theseatpostman.com/
will get it out no problem - not cheap but better than having to buy a new frame. He's removed a few for our customers and never failed even when they have been quite bad

Never heard of this before but good to know as a last resort. Thanks.

iPete

Subscribe!! Exactly the same issue, allu frame/carbon post.
What are people suggesting is poured down the seat tube?

I've heard suggestions from coke, ACF50, ACF30 to Effetto Mariposa Carbomove.

6wheels

Think Monty recommended AC90, being the best in his experience.

mikenetic

lpretro1 wrote:

The Seatpost Man: http://www.theseatpostman.com/
will get it out no problem - not cheap but better than having to buy a new frame. He's removed a few for our customers and never failed even when they have been quite bad

Second recommendation for him from me - had a couple of customer bikes done, very good service.

iPete

Any luck?

After a day upside down filled with coke and no obvious movement I got impatient with mine. With much force it did move but sticking an Allen key through the holes in the seat post was only going to rip it apart and leave me stuck without a bike.

Now I don't own a vice and looking around the garage I was struggling to think what could give me the leverage needed, except maybe that spare frame hanging up on the wall.. oh.



50 minutes with two of us twisting away and it finally came out. Happy days.

Worth a try..

fenix

That's almost genius. Or is it crazy. I'm not sure - but good work anyway.

keef66

It looks like bicycle sex to me! Leave them to it...

You might have a new unicycle in a few months

Monty Dog

FWIW Coke contains phosphoric acid which doesn't do much for aluminium oxide - there are more effective solutions such as ACF30. Beware of excessive force and mechanical methods - I have seat tubes unpeeled like a Coke can!