A fixed-gear bike, often called a fixie, is a type of bicycle that has a single gear and no freewheel mechanism. This means that the pedals are always in motion when the bike is moving, allowing the rider to control speed and braking by pedaling backward. Fixed-gear bikes are popular among urban cyclists for their simplicity and lightweight design. These bikes typically have fewer components than traditional geared bikes, making them easier to maintain. Riders often appreciate the direct connection to the bike's movement, which can enhance the riding experience. Fixed-gear bikes are commonly used for commuting, track racing, and recreational riding.