A fixed gear bike is bike whose socket is screwed directly onto the hub. In other words, there is no freewheel which would allow the bike to coast while the pedals are not moving. A fixed gear bike will cease to move if the rider stops pedaling. Conversely, if the wheels are turning, the pedals are moving. These bikes have specific advantages and disadvantages, depending on the kind of bicycling the rider wishes to do.GearsGenerally speaking, a fixed gear bike is a single speed bike. There is an exception, but not in the traditional sense. Some fixed gear bikes have a cog on either side of the wheel, allowing the rider a choice of two speed ratio; however, the rider may not shift speeds while riding. The hub, known as a flip flop hub, will have a fixed wheel cog on either side of the wheel, or a fixed wheel cog on one side and a freewheel cog on the other. In either case, the rider must manually remove, reverse, and replace the rear wheel in order to change the speed ratio of the cycle.UsesTrack bikes used in indoor bicycle tracks, called velodromes, are fixed gear bikes. Cycle ball, bike polo, and artistic cycling are also fixed gear bike sports. The fixed gear bike is ideal for track stands; these are tricks in which the bike remains stationary, while the rider balances it upright, with his feet in the pedals.Many young children's bikes are fixed gear bikes, as are BMX bikes. The popularity of the fixed gear bike has grown recently for use in commuting to school and work, under circumstances in which the terrain will remain constant and there are very few environmental challenges.AdvantagesA rider may choose a fixed gear bike for a number of reasons. First, they are generally light weight bicycles. Commuters often need to carry their bikes inside their office buildings, or up or down a flight of stairs. There are fixed gear bicycles that weigh as little as 23 pounds.Because the construction of the fixed gear bike is much simpler, maintenance is simpler as well. The brake systems demand fewer parts, and there is only one gear. Fewer repairs equate to less money spent and more time on the bike.Performance, although hampered in some ways, improves in wet conditions because feedback to the rear brake from the pedals encourages better grip on the road and better response to the conditions. This also is an advantage to a commuter, because weather can be unpredictable and safety may be better ensured with this bicycle.DisadvantagesWithout the ability to coast, the rider has little or no opportunity to rest on long rides; additionally, if the rider must rest, the bike will stop, potentially leading to loss of control of the bicycle. Novice riders of fixed gear bikes will also have difficulty in turning at higher speeds, as the rider does not have the opportunity, afforded by freewheel bikes, to equalize their pedal height during these turns. As a result, the pedal may touch the ground, possibly leading to loss of control.