A sad little 46cm Raleigh Rapide road bike was dumped on my doorstep a few months ago, and I just got around to rehabbing it. The problem is that the seat post in it is a 25.4, and the seat post it needs is a 25.8. The 25.4 will not fit snug enough to tighten up without doing damage to the seat tube. I have a pile of seat posts in the bin, but no 25.8's - a bunch of 25.4's, a 26.0 and a bunch that are bigger than that.

Can this be shimmed safely? Failing that, does anyone have a 25.8 post they can send/sell/trade me?