Removing stuck or seized seatpost?

Edgware road W2

I'm keen to give it a shot, how much do you charge?

first i do for few beer,and donation to the forum.

I'll take you up on that!

Ok,just let me know when.

So errrr I just did something idiotic.

Discovered the bike i was trying to convert to a rigid mtb commuter had a stuck seatpost shim, which was annoying. Then decided to hammer one of those locking nuts into it to give some purchase to hammer out the seatpost shim. Can’t hammer it out. Now have one of those locking nuts stuck in my stuck seatpost shim. Anyone got any suggestions? Might be one for that seatpost unsticking guy...

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If it’s only a shim that’s stuck, it’s probably only a couple inches long. If it’s not too tight you could try tapping it down and folding in the shim. Or risk knocking it all the way down out of the shim and hope it doesn’t catch in the seat tube.

Alternatively you could try putting a longer bolt in the star nut and attach something on there that will let you whack it with a hammer to try pull it out. Just a bit of angle iron with a hole in would work.

Also keep in mind folding the shim in. If you can get the star but out of the way it would get that shim out really quickly

Wise words, will give that a go. Unfortunately im not sure the shim will fold as the split in the shim doesnt go the full way down

Is that definitely a shim? It looks hella thick but that could just be the lip?

If it's a shim just bash the star nut right through and it'll fall out the bottom then fold the shim in on itself, it should be pretty flimsy.

Ammonia through the seat tube via the BB, anyone tried this?

Haaaa so i got the star nut out by working it backwards with a hammer on both sides.

However, having shone a torch down the hole, it appears the ‘shim’ is in fact a seatpost someone creative has cut down before fitting a smaller dia. seatpost inside.

So errrm anyone know a lbs that might be able to resolve this one?

Bikefix at Lamb Conduit Street would be a good shout.

Thanks, dropped them an email.

I would get a reciprocating saw on that.

or get a bit of pipe and weld a lip to it and something at the other end to allow you to hit it upwards with a hammer.

slot it in under the 'shim' and whack the crap out of it.

it will work, I had to do something similar a couple weeks ago where the seat post was cut close to the frame. I cut it too close, by accident.

Unfortunately I don't have access to a reciprocating saw. Bikefix will do it; they melt out the ally seatpost using a torch for £60, however, I'm minded to give the hacksaw blade by hand a go first so I don't end up having to anihilate the paint. Anyone had any luck with this, and if so, how many hours of sawing are we talking?

Given the post is cut flush to the seat tube, I'm thinking I may need to cut a couple of slots into the post before knocking the pieces downwards into the frame to disconnect them from the inside of the seat tube.

they melt out the ally seatpost using a torch...

Yeah, I’d be giving a few other things a try before putting that amount of heat into it.

Hacksaw blade by itself is a fools errand. Get a dowel, cut a slot (with the hacksaw blade or another saw) and glue the hacksaw blade into it, the dowel will keep the blade rigid and make it a much easier job.

Aluminium expands a lot more easily than steel under heat. Heating it would only get it more stuck I thought. You would need to cool the post and heat the tube

I think they heat the frame to above the melting point of alu >660C but below the melting point of steel ~1250C. Sounds a bit terrifying but apparently pretty reliable. Would also mean taking cables brakes etc off the frame.

Just use the smaller post size and leave the shim no ??

Quill stem into the 'shim' tighten, place into vice and twist?

‘Shim’ allows for 22-23mm post so not ideal.

Quill stem will put outward force into post/tube so not sure whether this might just compress the post into the tube and making it more difficult to move? Going to give this a go prior to hacksaw anyway.

Sounds like a good way to loose that seat clamp and any cable guides and even brake bridges etc that are silver brazed in place.

Hacksaw blade appears to be doing the trick. This is the product of 3hrs of constant sawing. Haven’t made it the full way through lower down but reckon a hour or so tomorrow and should be there. Once the two slots are fully cut I’m hoping I should be able to get the rear half loose by hammering something like a screwdriver in behind.

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I would be very careful about hammering a screwdriver down the back. it's a good way of either splitting the seat tube, or getting the screwdriver stuck as well...