This thread on testing a bike is interesting but harbors some assumptions about the purpose of a test ride. As a part-time bike salesman for 10 years, I agree that a 15 minute test ride in a parking lot is not going to tell you everything about a bike. But... it will give you a "feel" for a bike that is valuable. For instance, you can tell if you are too stretched out or too cramped. How safe do you feel? That is, is the bike too big or small? My customers frequently ride similiar bikes from different companies at the same price point and love one and hate the other; that's ok. I firmly believe in trying a bike; you wouldn't buy an expensive suit or dress without trying it on. The ultimate test will be the first couple of hundred miles but at least with a test ride, you may know if you are in the right ballpark with the bike. This assumes that you bought the right bike for the right kind of riding and it is fitted properly. Without these assumptions, all bets are off.