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Seized Carbon Seatpost

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  • December 26, 2014 at 8:43 pm #22903
    SnowdoniaClimber

    I am now starting to set up my new summer bike which has a carbon frame and a carbon seat post. The seat post has stuck and no amount of shear force will make it budge. There is an aluminium sleeve between the seat post and frame if this makes any difference, which I sense it will. I really don’t want to damage the frame but I am prepared to damage the seat post if it will allow me to put a new one in. Does anyone have any secret tips or ways of releasing the post from the frame?

    Things I have tried from reading around:
    – Rotating with all the force I have
    – Pouring hot water over the area repeatedly over a few hours and then trying to move it
    – Poking it

    Any tips would be encouraged and greatly appreciated, thankyou!

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Viewing 11 replies - 1 through 11 (of 11 total)
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  • December 30, 2014 at 2:32 pm #824225
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    untakenname

    If you haven’t already try
    If you haven’t already try some plusgas on it as I freed a friends seatpost with it that hadn’t been moved in over a decade, it works wonders with seized bolts on cars as well.

    I had a similar issue with a stuck bike post, tried all the usual methods to remove it but it was seized solid so had to resort to grinding it out bit by bit.
    Luckily I was off work at the time recuperating from a crash and the Vuelta was on, took a few hours, the heat generated was immense, had to stop every few minutes to let it cool down. Once the post was thin enough I could grab one end with some pliers and roll it off http://road.cc/sites/default/files/bikeseat.jpg

    December 29, 2014 at 7:15 pm #824223
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    SteppenHerring

    Sounds like you haven’t tried
    Sounds like you haven’t tried swearing at it.

    December 28, 2014 at 3:09 pm #824221
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    MartyMcCann

    Just a few words of warning
    Just a few words of warning if you do have to go down the cutting it out route (from bitter, personal experience).
    Make really, really sure you have the time and fortitude to see it through to the end otherwise just take it straight to your LBS before you start cutting. My normal LBS didn’t want to touch mine with a barge pole so I had to start the job myself. After 3 days of soul- and mind-numbing sawing ~X( ~X( ~X( (and replacing quite a few blades) I realised that no matter how straight I was trying to keep the blade I was starting to cut into the frame. At that stage my mood was so low I had mentally written off the bike and was desperately trying to work out how I was going to be able to afford a new one. Do not underestimate what cutting into your pride and joy will mean to you! Luckily one of the fellas in my club is a mechanic in another bike shop and he told me to bring in what now looked like a frame with a peeled aluminium banana stuck in it. Due to my efforts it took them much longer than if I had brought it straight to their shop without cutting but luckily enough I told them I didn’t want to know what they did to try and free it. I got a surprising call a couple of days later to hear that they had freed it-I didn’t want to ask how they managed it (and to be honest I don’t think they wanted to tell me!). Needless to say when I am going to buy my next bike I will be more likely to go to them than the original shop.
    Basically I am just suggesting that, while you may want to do the build yourself, if it comes to the scenario where nothing else works and you are going to have to cut it out, seriously think about an LBS before making the first of very, very, very many cuts.

    –

    December 28, 2014 at 11:47 am #824219
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    crikey

    Quote:It’s probably not

    It’s probably not Aluminium Oxide causing the problem, it’ll be the grease you used on the post causing the post and possibly the frame to expand as it’s absorbed.

    Nah. The interaction between grease and carbon is an old cycling wives tale. It’s galvanic corrosion between the alloy sleeve and the carbon post.

    Cut it out.

    http://www.corrosionpedia.com/2/1556/corrosion/galvanic-corrosion-of-metals-connected-to-carbon-fiber-reinforced-polymers

    December 28, 2014 at 12:03 am #824217
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    Initialised

    It’s probably not Aluminium
    It’s probably not Aluminium Oxide causing the problem, it’ll be the grease you used on the post causing the post and possibly the frame to expand as it’s absorbed. So an ammonium etch of the surface layer of AlOx on the sleeve may not work how it can for an Al post in a steel, Ti or Al frame.

    The chemist in me says that you need something to etch away the Al sleeve that wont damage the resin on the carbon fibre or anything else it comes in contact with. Sodium hydroxide (lye/caustic soda dissolved in water), methoxide (dissolved in methanol), or ethoxide (dissolved in ethanol) may do the trick but check it wont damage the frame first.

    The engineer in me says, heat twist and pull, that worked for me last time I got a CF post stuck in an Al frame. I made the mistake of swapping saddles with another bike by swapping the seatpost.

    December 27, 2014 at 7:56 pm #824215
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    crikey

    Get a long hacksaw blade and
    Get a long hacksaw blade and cut it out.

    You can spend days messing about with various witchcraft style lotions and potions, and heating and cooling and praying and other arcane mystic stuff, but the simple, straightforward works-every-time answer is to cut it out.

    December 27, 2014 at 7:51 pm #824213
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    monty dog

    You could try some ACF50
    You could try some ACF50 which is pretty effective on aluminium oxide which is what has formed to ‘stick’ your post. Final resort is hacksaw blade.

    December 27, 2014 at 11:11 am #824211
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    glynr36

    Heating/cooling doesn’t work
    Heating/cooling doesn’t work on carbon.
    http://sheldonbrown.com/stuck-seatposts.html
    Scroll down to the one for carbon, had a mate use that method to great success.
    Worst case you’ll have to chop it out, don’t bother heating and cooling on carbon, especially with heat.

    December 27, 2014 at 1:20 am #824209
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    The _Kaner

    Kill it with FIARRR!
    Kill it with FIARRR!

    December 26, 2014 at 11:32 pm #824207
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    ChuckB

    This is going to be a bit
    This is going to be a bit drawn out, wrap the seat post in some rags, pull the bottom bracket completely out, leave the seat intact. Support the bike upside down, run a garden hose through the bottom bracket hole, just down far enought to be near the seat post. Hook the hose up to a co2 fire extinguisher, pour a lot of really hot water over the rags and get them soaked, allow 2-3 minutes for all the parts to heat up. put a foot on the seat Assy, then activate the co2 fire extinguisher into the seat post. Start sharply pulling up and pushing down on the frame, whilst holding the seat with your foot, you are going for quick thermal shock to try to separate the parts so you only have at most, 1 minute to try this. I have seen this work on a frozen aluminium seat post, and I would state that this technique is not without a bit of risk on CF.

    December 26, 2014 at 10:25 pm #824205
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    Flying Scot

    So you have a carbon post
    So you have a carbon post seized in an alloy sleeve that is seized in a carbon frame?

    If so, I hope someone else has an idea.

    Ammonia is the usual job if it’s aluminium oxidisation that’s the problem, but hard to tell if it is. Might be a job for a hacksaw blade.

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