Thanks, mimi, but what I am trying to see are the undersides, where the usable part of the rails end relative to the back of the saddle. Maybe its easier to just take that measurement. I checked all the brooks online stuff and they don't show the undersides. Don't worry Lisa, if its too much trouble I can ask the guys at wall bikes to measure it for me. I am just intrigued now about the B68, but it is soooo muuch heaver than my finesse so I want to know if it will really make a difference.