Shims, Good or Bad Idea?

[HLaB]

When I replaced my Kinesis GF last year they've increased the diameter of the frame from 27.2mm to 31.6mm. The lbs put in a Orbea alu 31.6mm as a temporary measure but I have a good selcof 27.2mm carbon post. The alu post began to bond a few days ago with my ti frame, I removed it in time but I am thinking of using the 27.2mm carbon post with a shim; thermoplastic ones seem to be the best to stop things bonding. What do folk think are Shims a bad idea or not?

Edit
A few things Ive read:

http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=107160

http://singletrackworld.com/forum/topic/seatpost-shims-good-or-bad

 

[fossyant]

Hmm, ideally I'd use the right size post especially with carbon - you want the stresses transferred to the whole post, rather than a limited section of post where the shim is.

Go buy a nice new shiney Carbon post. Make sure its a posh one ! N+1 on upgrades too !