I am currently riding a 16 inch 4500. Today at my LBS I tried out a 17.5" 6700. My first thoughts about the bike were :thumbsup: this is nice, very nice. The frame felt pretty good, but alot different than my 4500, but it felt like it was kinda big, if that makes any sense. I'm 5' 8" about 170 lbs. I know that I need to try a 15.5" and I am going as soon as I can, but could the 15.5" be more closer to the size frame that I need? Or will it probably just take a little getting use to the different geometry? Any thoughts would be greatly appreciated!