Originally Posted by RonH
Go to the shop that sells the bike you're looking at and let them do the fit. After your bike is "set up", you tell them what feels right and wrong about it so they can make the changes.
Yes, good advice, but I was hopoing to buy a winter/trainer bike on-line, and don't know what to get. I guess a bike 2cm bigger than my current ride would be safe, but I'm guessing it should even be a little bigger.