Fixie bikes are kind of best single speed bikes to use for urban rides, messenger purposes and as a winter cycle, due to its simple structure and less components assembly. With a fixie bike, you keep pedaling during the whole ride, which generates good amount of heat in your body (the thing you need the most in winters). Also, since there is no shifters, the fixie offers less distraction and you can easily use it as a messenger bike or for long urban rides.