Fixed Gear for Beginner: Fixie 101
A fixed gear bicycle or Fixie is a bicycle that has no freewheel, meaning it cannot coast — the pedals are always in motion when the bicycle is moving.
The sprocket is screwed or bolted directly onto a fixed hub. When the rear wheel turns, the pedals turn in the same direction. This allows a cyclist to stop without using a brake, by resisting the rotation of the cranks, and also to ride in reverse.
Any enthusiastic cyclists ride such bicycles by choice, at least part of the time. Why would anybody do that? It is not easy to put into words. There is an almost mystical connection between a fixed-gear cyclist and bicycle, it feels like an extension of your body to a greater extent than does a freewheel-equipped machine. If you are an enthusiastic, vigorous cyclist, you really should give it a try.