Shimming carbon seatpost?

Hey!

My colnago takes a 27.2mm seatpost, but it's really really fussy which ones it takes...

I tried about 5 aluminum posts in the past and only 1 of them fitted the frame, but due to airport security, I no longer have that seatpost.

I recently purchased a cheap 27.2mm Seatpost off eBay in the hope of it fitting, and it does (kinda...) but even when 'comfortably' tight, it still moves a little.

What're my options? Straight to carbon paste or try and shim it with a can? Does anyone have experience?

Thanks!

Straight to carbon paste

Is that not the way to go immediately?

did this to mine. get a innertube and cut a small strip, basically you are using that as the shim. gotta put the seatpost in with innertube strip at the same time. feed the seat post in but have a piece of inner tube sticking out by holding it so it dont go in.

I haven't got any to hand, but I get the feeling I'll add carbon paste and still have this problem because my Colnago is super fussy which 27.2 post it takes

Hmmm, very much doubt I'll get an innertube in there! I may be struggling to get a piece of coke can in there

Update:

just cut up a can of Italian (no less) tonic water and used it as a shim. It works perfectly! None of the can is protruding above the seat-tube and it's away from view at the back of the frame area. Result!

Thanks for the input all.

This is dependent on the can in question obviously, but with the thinnest can you can produce at the moment having a wall thickness of 0.1mm, youd be be looking at a 0.2mm loss of ID for the seat tube, which is well beyond manufacturing discrepancies. Have you definitely got the right seat post size?