rearhub

A rear hub is a critical component of a bicycle's wheel assembly, located at the back of the frame. It serves as the central axis around which the wheel rotates and houses the axle, bearings, and often the braking mechanism. Rear hubs are designed to accommodate various drivetrain systems, including chain-driven and belt-driven configurations, and may feature either fixed or freewheel mechanisms.

Fixed rear hubs provide a direct drive connection between the wheel and the pedals, allowing the rider to pedal in both forward and reverse directions. This design is commonly used in track racing and fixed-gear bicycles. In contrast, freewheel hubs incorporate a mechanism that disengages the chain from the wheel when the pedals are not being turned, enabling smooth coasting. Modern versions often include a ratcheting system that allows the chain to move freely in one direction while remaining engaged in the other, facilitating efficient pedaling.

The construction of a rear hub typically includes an axle, bearings, and a flange assembly. The axle extends through the hub and is secured within the frame dropouts. Bearings reduce friction and allow the wheel to rotate smoothly, while the flange assembly supports the spokes that connect to the rim. Some hubs incorporate integrated braking systems, such as drum brakes or disc brake mounts, enhancing stopping power.

Rear hubs are available in various sizes and configurations to suit different bicycle types, including road, mountain, and hybrid bikes. The choice of hub can influence performance, durability, and maintenance requirements. Proper installation and regular maintenance, such as lubrication and bearing inspection, are essential to ensure optimal function and longevity.