Originally Posted by mcoine
First, its 3mm difference not 2mm, 1.5mm on each side, and no way would you want the post to move that much while in the frame. If its an aluminum frame, the situation is even worse. Just get the right seatpost.
Was not saying to use the seat post unshimmed, just saying that though flex would occur, probably not catastrophic if post is shimmed and inserted past minimum distance.