To start i'm a big guy that got hooked on bike for the freedom and help shed the pounds. I'm 6' and a little over 300 lbs. I ride trek 7300 fx hybrid. It was great in the beginning. Now that my mileage is going up( usually around 25-30) , sitting up straight is bugging me. I keep raising the seat post to get a little more comfy. I was looking in to road bikes. I rode a friends trek 1500. it felt good, but due to my size , I was wondering if that was the bike for me. A friend at work told me about cyclocross bikes like the cannondale and the trek xo1. He told me just to ditch the knobbies and get road tires. My bike allowance is 1500 and i usually ride the local bike trails and the back roads around my town. I'm a newbie at all this, and would apreciate any help thanks