Well let me take you in to the dark seductive world of ridding fixed gear. Not for the weak and faint of heart and Warning: Once you go in you may not go back.....Ha, Ha, Ha
Ok so what is a fixed gear bike? Basically bicycles that were originally designed to race on a track or Velodrome. These bike had only one gear and no brakes. Why no brakes? Well these bikes were being ridden fast on oval tracks. Riders are drafting inches from each others wheels. Touching a brake would not give the riders in the back time to react which would result in lots of crashes. Track riders were conditioned to go around problems and obstacles to avoid trouble.
So how did these bikes become popular on the streets? We can thank the New York Bicycle Messengers. If you don't know what a messenger is get your hands on the movie Quicksilver with Kevin Bacon. What's different about a fixed gear? 1) As long as the bike is moving the cranks are turning. There is no coasting on a fixed gear. You have one gear solidly fixed to your rear wheel if you pedal backwards the bike moves back if you pedal forward the bike moves forward. Kind of like that tricycle you had when you were a kid. 2) The bikes are lighter than similar road bikes, because you don't have the extra weight of gears,derailleurs and shifters. 3)The crank arms are shorter to allow you to keep pedaling through a curve.
So.....Why would you want to ride one of these bikes? 1) They are great fun! 2) You have control on these bikes that you don't get on any other type of bike. 3) Since you are direct drive you feel at one with the road a truly Zen like experience. 4) Simplicity nothing complicated the true essence of biking.
So if I peaked your interest continue on.. if not then you don't belong here and get the hell out!