I have used (quite reliably) shims cut from 2L soda bottles for running a pair of 25.4 bars in a 26.0 stem, as well as seatpost shims--sizes forgotten. It seems dimensionally stable and will never seize, not that that is really all that likely to happen on my watch.
IIRC, soda bottles measure ~.2 mm, multiplied x 2 naturally in this case. I have handy a micrometer, but not an empty bottle. This is all more of a BOB type thing than a CR thing I suppose, but all parts and frames were on-topic!
Jeff Slotkin Charleston, SC US
On Nov 1, 2007, at 10:26 PM, Charles F Nighbor wrote:
> One way to get the correct fit for your frame is get a 25.0 mm seat
> and buy a shim to fit your frame seat post dia.
> Made by Ultimate Sports Engineering
> Shim size/weight chart
> Shims are available in Aluminum and Thermo Plastic, despite the latter
> being a lighter solution its material characteristics limit the
> thickness of the ID - OD measurements. Aluminum is used to achieve the
> thinnest shims as it is a more robust material.