I'm no physicist, but I have to join in saying that the too-long-post-causes-frame-damage theory seems crazy. Is the idea that if the post goes deep into the frame, it gives you leverage with which to bend the tubes of the frame (by applying your mighty weight to the saddle)? Seems to me that the exposed part of the post would bend and break first. This seems like bostontrevor's area of expertise... trevor?