I want to pick up a Cannondale racer I saw on CL and have some question about sizing and how to do it. I'm entirely new to cycling so maybe this is a little advanced to start with but here we go. How do I determine if a bike is the right size? Is it a frame measurement that determines whether it's the right size? Can the tires on these support 190 lbs? They look thin. They are asking $650. Is that a good price? It has 63 cm carbon fiber forks, aside from that I have given the rest of the info I know of. I've contacted the seller and I'm waiting to hear back. Are there things I should look for if I get a chance to ride it? Should it feel right if it's the right size?