In my haste and exuberance to build my bike up I stuck a shim in (to see if I could get away with a 27.2 seatpost). It looks like its a 26.8 shim though.. but anyway.

Its stuck solid. soaked in WD40 overnight. With large pliers clamped all the way round I found I could rotate the shim out slightly- but this then rounded the metal making another similar attempt possibly too difficult- following this theme-tonight I was going to buy a big adjustable monkey wrench. This should do it?

Its steel (or alu) on alu frame.

Ideas and tips?

If it is split all the way down, try to fold it in on itself. If not, you need something that will lock on (molegrips) so it can’t slip. A slide hammer might also work depending on the length of the shim

Molegrips- thats the word I was looking not monkey wrench.

If you could put a bit of tube slightly into the shim, THEN get some FO-molegrips onto it, that should grip it without crushing it.

Molegrips would do it. Lock them up *really* tight on the lip and it’ll let you twist/pull it out. I wouldn;t worry about compressing it – just put the grips on one edge.

Hacksaw blade down the full length of it from the inside?

Cut a split in line with the seatpost split so it’s then in two halves, should fall out then.

Just be careful not to cut through to your frame!

Think id be hacksawing down the length of the frame slot to aid folding it in on itself.

Drill into it through the stress-stopper hole at the bottom of the slot then lever it out using a hard steel lever such as a thin file end.

Obviously your lever will need to be able to fit in the slot as it rises.

Yeah, moleys and pull. If you can get a squeeze onto the shim too that’d help but quite likely not neccesary

Fashion up a slide hammer from a long bolt, & it should come out.

Failing that, a hacksaw blade wrapped in a rag blade & chop along it’s length internally.

Fashion up a slide hammer from a long bolt

Hang on- I’ve got a long threaded metal rod with bolts/plates on that I use for headset fitting. That’d do it/help with the molegrips? (minus the plates)

This stuff (also comes in a stray) is great at shifting stuck posts:

http://www.ebay.co.uk/itm/like/171296124295?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=108&ff19=0
totally immerse the area you need coverage in it and be patient, 24hrs or more. Then go to town on heaving it out.

Given the shallow length though, i’d other wise cut it along the length (as mentioned above) with a fresh quality long hacksaw blade via a chop saw or bodged together alternative.

Phil at Evans cycles Chill Factor saved the day. 😀