sons been given a racer and despite oil soaking and ****ting with a hammer(downwards) the seat post wont budge.removed the pinch bolt and prized open the top of seat tube slightly but to no avail.oh and its one of those silly ones with grooves machined down the post to allow plenty of rainwater in.any good tips?
PS points deducted for “just buy a decent bike ya cheapskate” comments.
cheers!

Heat might work. Leave it by a radiator for a couple of days.

aparently ally expands twice as fast as steel so freezing it would help in that respect.would have tried this if, A.i had a chest freezer. B. i actually thought there was any chance of it working!

Lots of penetrating lube, leave for a while, clamp seatpost in a vice and use the frame for leverage.

Use Plus Gas or similar release agent, oil not really good enough, keep soaking over a few days, Try heating with hair-dryer but carefully not to damage paint.

Level 1
BB Out pour a good penetrating oil down the seat tube with the bike upside.

Seat post in a vice use the frame as a lever to twist.
No vice drill a large bore hole through the seatpost insert a steel bar as a lever.

Level 2
Heat Kettles of boiling water poured down the seat tube followed by cold water.
Blow torch to the seat post only (to save paint on teh frame)

Level 3
Caustic soda down the frame.
Lots of heat on the frame (paint shagged)
Beg borrow a reamer. cut the seatpost off and ream it out until it collapses.
Can’t get a reamer? cut the seatpost off and use a hacksaw blade or a angled file to cut through the pside of the post.

Let us know how you get on.
Cheers
paul

Go for the chemical warfare. Sodium Hydroxide (soda crysals) will disolve the aluminium oxide that has formed to cause the tight fit but isn’t going to harm the steel (might spoil the paintjob though!

Soak in Coca Cola, is a option i heard used but have no direct experience with. At least if it doesn’t work you could drink it after.

Pee on it! Well, pour stale pee on it… 😀

or use ammonia.

halfrauds have freezey stuff in a can?
spray it down the inside of the seatpost and see if it will break the seal?

that or crush the crap out of the seatpost with a monster molgrip/vice, and take the frame off the seatpost (rather than the seatpost out the frame)

indicently, you will probably find, if you DO get it out, they will both be in excellent condition.
and will all of a sudden, for no dicernable reason just come free.

its all about the leverage to break the initial chemical weld

The Halfords freezy-stuff-in-a-can is pants – you may as well pee on it. I’m in the same boat, and am a bit stuck for a solution. I’ve started down the cutting-it-with-a-hacksaw-blade route, but there just must be more to life than doing that…

I’m waiting for a neighbour who’s a retired engineer and has reamers, lathes, vices etc in his garage to take it on as a project…

I’d read about Coke, ammonia, heat / chilling it – but haven’t tried them yet. Maybe CO2 canisters would work? I don’t want to shag the paint on mine, and the seatpost was shot anyway, so I don’t mind damaging that.

Best of luck.

after you’ve mangled the exposed bit of seat post, try using a long, thin saw blade to cut a groove lengthways into the seatpost (taking care not to cut the seattube on the frame). You can then crush the post and remove it.

Rather tedious, but I’ve seen it work several times.

http://www.singletrackworld.com/forum/topic/help-stuck-seatpost-in-a-steal-frame

pretty much same advice
luckily i knew a mechanic who helped me in the end
a dirty great big vice was used to clamp the post, and then using the frame as a lever,

HI There

how long should l leave the coke to soak before attempting to remove post?

Thanks

Warren

Sheldon brown has good tips on this

heat won’t be much use as the steel expands less than the alloy unless you can manage to heat the frame and cool the seatpost.

as a last resort melt the aliminum post out, be carefull though!