What exactly does a shim do for you? I assume it "mates" a bigger seat tube to a smaller seat post, but why wouldn't you run a larger post in the first place? Am I missing something?GumbaFish said:Good morning all. I can't wait untill tommorow or friday when I will get my seatpost shim in so I can ride again. I guess its better anyways, I need to be studying and not riding right now.