WHAT IS A FIXED GEAR CYCLE?

So What is a Fixed Gear Cycle or Fixie as it is popularly called? How is it different from any other cycle you have seen or driven? 

A fixed gear cycle is basically the simplest form of a bicycle. On a fixie, the rear cog which is the small wheel with teeth on it (see image below) onto which the chain engages doesn't have the Pawl and Ratchet mechanism. In a normal cycle with a freewheel, this mechanism engages the gear when you pedal in the forward direction and makes the wheel free when you pedal in the reverse direction or do not pedal. With this system absent on a fixie, you can power the rear wheels by pedaling in both forward and reverse directions. But generally back pedaling (pedalling backwards) is done to brake the rear wheels which is why you don't see brakes or only a front brake. Essentially you are always in control of your bike and feel closer to the road. A fixed gear drivetrain is mechanically more efficient than the traditional freewheel ones and you reach higher speeds. 

Fixed gear Cog

Freewheel Cog