Single-speed bicycles are designed with only one gear ratio, meaning they have no gear shifting options. This simplicity makes them lightweight and easy to maintain, as there are fewer components that can wear out or require adjustment. They are ideal for flat terrains and urban commuting, where riders can maintain a consistent speed without the need for complex gear changes. These bicycles are often favored for their minimalist design and straightforward riding experience. Riders can enjoy a more direct connection to the road, making them a popular choice among city cyclists and those looking for a low-maintenance option. Brands like Schwinn and Trek offer various models to suit different preferences.