Tips for getting a stuck seat post out

After a winter of neglect and snowy commuting, the post on my commuter is stuck fast. Any tips on getting it out? i’ve tried firing some degreaser in there but i don’t think it’s penetrating. :roll:

extreme means to solve extreme problems: Take the seat off, stick the seatpost into a clamp, with the bike upside down, clamp tight, and use the frame to torque it free. If necessary, take the bottom bracket out and pour the degreaser or light lube or something like that down there.

Sometimes it’s easier to just use a junky saddle clamped to the post instead of a wrench or workstand, since you can often get a more secure hold that way.

Then there are two Sheldon Brown tips: If the degreaser/lubricant solutions don’t work (I’ve had best luck with Tri-Flow for this application,) sometimes you can get it unstuck by heating or cooling the seattube or seatpost. If the two are made of a different material (steel and aluminum, for example,) one will expand/shrink faster than the other, which can loosen the chemical weld that sometimes happens between two different metals. I’ve had luck with this technique once or twice. As a last ditch the seatpost can be cut off an inch or so above the seat tube, then cut straight down across its diameter - you then clamp the two sides together with a vise, which can sometimes break the corrosion.

Steel/Steel: Liquid Wrench in repeated applications and tap with a hammer.

Steel/Aluminum: Brute force. If you can’t get it out first with a saddle and then with the frame in a vice, it might never come out.

Apparently ammonia works (concentrated stuff, not the cleaning ammonia you buy at the grocery store). Last time I had a badly stuck seatpost I tried a bunch of different penetrants for about a week each and it just didn’t happen.

You need to use a good penetrating oil and/or very inviscid solvent to attack the oxide from both sides of the seat post (remove the BB)

My super weapon against just about anything nasty is nitromethane (never tried it on stuck seatposts, want to?), you can also try a chlorinated solvent (Perchloroethylene, Trichloroethylene), hydrochloric acid can probably attack the metal oxides sticking it as well.

As a last resort you can cut the seat post off and mill the stuck section clean out of the frame - I did this for a friend of mine and it turned out ok.

Mikes suggestion of playing with heat can work too but you often need to bring in serious temperature differences - you can get liquid nitrogen on campus, although i’ve never had any luck using that stuff to fix overly tight press fits or extracting stuck parts, but it is REALLY fun to play with.

A hairdryer worked for me once. Did you get the thing out yet?

If you have a steel or aluminum frame that is pretty beaten up, this will work when it is very stuck… (while putting the seatpost in a vise for sure to pull on it at the same time)

i have been procrastinating this problem and will likely look at this in Aug. when i have the time a fortitude to address this.

Thanks Mike, John and others for the advice. i’ll post here again when i have an update!