We probably all have bikes that are a perfect fit and we mostly know what size bike gives us that sweet spot where the fit is just right on. But most of us also have bikes that are a size larger or a size smaller than our perfect size. We have these bikes because one or two bikes is not really enough and let's face it.... variety is the spice of life. Duplication is boring. Well my question is how does sizing affect ride performance? I would guess that a slightly undersized bike would tend to be more responsive and perhaps quicker to accelerate while a slightly oversized bike may be more comfortable and an easier "all day" rider. I realize geometry, bottom bracket height, etc. is part of the equation but leaving geometry out of the discussion, what I am really interested in is how a slightly undersized or oversized bike (one size up or down form that perfect fit) affects climbing ability and also stamina. Which bike would be a better climber and which bike would tend to wear you out quicker, one that is slightly undersized or oversized?