Quote Originally Posted by Hi Ho Silver View Post
It could be due to many things-
-the grease in the wheel bearings is "packed up" (sorta solidified)
-the freehub needs cleaning & lubrication
-the wheels are not tensioned properly
-tires a/o tubes are clunkers
-the frame is misaligned or the dropouts are misaligned.

Frame and/or dropout misalignment (i.e., the front and rear wheels are not spinning in exactly the same plane) is often overlooked, but I had this problem on one of my bikes and the effects are very noticeable.
Those are all interesting possibilities. How easy is it to determine any of these possibilities and diagnose? The tubes and tires would be my last suspicion. I have Kenda Nevegals, which people around here always seem to rave about.

What is so frustrating is all the glowing reviews I read of the Cannondale F5. I have a friend with the EXACT same bike (Cdale had a bunch of the petite size sitting in a warehouse and essentially liquidated them about a year ago). She rides far less than I do and on the road with our road bikes I can ride circles around her. On trails I can barely keep up with her and end up beating myself up trying to do so.