A fixed gear bicycle, often called a fixie, is a type of bike that has a drivetrain with 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 for their simplicity and lightweight design, making them ideal for urban commuting. Riders of fixed gear bikes often appreciate the direct connection to the bike's movement, which can enhance the riding experience. Additionally, many cyclists enjoy customizing their fixies with unique colors and accessories, contributing to a vibrant subculture within the cycling community.