MARK, without a doubt, buy the large. At 6'1", no worries. You'll look over. I'm 5'7 1/2" and I actually do look over with good posture. I road longer yesterday and actually felt like I handled the bike better and more comfortablly while correcting for posture. At a slouch I can still sort of look over, or through, but to me it's at that uncomfortable middle line or eye level. I was thinking medium might be better, but now I'm thinking I actually might prefer the large even at my vertically challenged height.