Removing stuck or seized seatpost?

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  • @SlimCharles can I ask what your sticking the hacksaw blade too to get it into the seatpost?

    MY croix de fer has a well and truly stuck seatpost (previous owner mistreated it) and it's ever so marginally too low.

  • I had a mini hacksaw (the type where the blade projects beyond the handle) with a long blade. Once I’d made the initial notch with the hacksaw I then reverted to using the blade on its own, using a rag wrapped around the end of it to protect my fingers although this was super slow going. Haven’t had the chance to go back sawing since so its still not quite made my way through. I think I’m going to hit it with some WD40 for a few days once I’ve fully made it through the seatpost. Not sure what the plan is at this point for extraction though. Also, this rockhopper cost me 40 quid so if this goes wrong it’s annoying but not the end of the world. Best of luck!

  • I recently got a alloy seatpost out of a steel frame using caustic soda. It corrodes the aluminium but not the steel. It does damage the paintwork but if ur careful (keep it on the inside of the frame) there will be no damage.

  • I'm toying with doing this too. Living in an apartment at present though, and fancy getting my deposit back. New house (so long as the bank gives me money) needs a tonne of work so I can wait til I'm there to try that or the saw method.

  • Have you tried the threaded-rod-and-washers-DIY-seatpost-pu­ller?

  • Had to do this stuck seatpost malarkey a couple times lately but it’s been successful without damaging the frame.

    The other week I had a stuck stem, drilled a big hole through the middle and sliced some slots in the edges with an electric saw, stopping before it broke through to the steel and chiselled them out with an old screwdriver. Took ages and was a massive pain but got it done. Only thing I would say is if you use an electric saw is that it can hammer the remaining part further down so leave an edge if you can do that doesn’t happen. I cut it flush to the top of the steerer which was a mistake in retrospect.

    Yesterday I had a seatpost stuck with about 3” in the frame. 1” diameter post which is 25.4mm.

    Used a 25mm drill bit to drill it out. It was stuck hard to the very end, see the pics below for before and after. Had to keep it dead straight so it didn’t cut in to the frame.

    This also took ages, about hour and half.
    With the stem I drilled a 16mm hole straight through with no issues. With the seatpost it was getting very hot very quickly and heating the drill up very fast. Presumably due to the bigger size. Had to use lots of cutting oil and water on the frame to keep it cool and cut with the drill in a few half second bursts pulling out the drill to get the dwarf out and spray oil in. It got the seat post out and since it was so far extended out of the frame there was about 12” of remaining seat post left to use.

    If I was to do again I would wrap a wet towel around the frame to help with drawing the heat out.

    Big drill bits can be bought from toolstation for under a tenner and use on a regular drill chuck.

    Use a low speed low torque setting as the drill can bind up quite easily. Use lots of oil to help cutting and keeping heat down.

    Both of these were pretty much welded in the frame so very much a last resort.

    Hope that’s some help.


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  • I recently picked up a bike for my partner and unfortunately it arrived with a seized seatpost. It is an aluminium post in an aluminium frame. It is possible to rotate the seatpost round using the saddle for leverage but impossible to get the post to move upwards at all. So far I have been soaking it in WD40, as I am under the impression that plus gas won't work if it is alloy on alloy... would coke make any difference? Is there currently a seat post seize expert on this forum able to help?

  • @ghostface I think if you've got it moving it should come out however being able to hold the seatpost or frame securely enough and twist is tricky.

  • Cheers @TheShipwright- thanks for the advice. The tubing is 7020 oria, I don't have my calipers to measure but I wonder if it might be a 27.2 seatpost forced into a 27 seattube. I've read conflicting things on the internet about the seat tube internal dims of 7020 tubing. There is no discernible ripple in the seattube but suspect if it was only .2 of a mm this wouldn't be so obvious. My partner already took it to a bike shop who put it in a vice as I don't have access to a vice - and they said it was so tight that it was causing the worksurface to lift. They quoted £100, but as an unknown entity due to not knowing how long it might take. Nightmare

    Does PBlaster work on aluminium on aluminium or not? Or would another penetrating oil be better?

  • Just spoken to The Seatpost Man who was full of helpful advice. Will follow his advice and see what happens soaking for the next week. He told me his is now up to 1500+ successful removals!

  • @ghostface it think it unlikely that a 27.2 post would go into a 27 tube, its much more likely stuck via neglect.
    What did the seatpost suggest to try?

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Removing stuck or seized seatpost?

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