hjulnav

Hjulnav, or wheel hub, is the central component of a vehicle wheel that connects the wheel to the axle and serves as the mounting point for the wheel itself. It is a key part of the wheel assembly and plays a central role in transmitting torque and supporting the vehicle’s weight.

In modern road vehicles, the hub typically houses the wheel bearing, provides a flange for wheel studs or bolts, and carries the brake rotor or drum. Many hubs include a seal to keep grease in and contaminants out, and often a sensor ring for the anti-lock braking system (ABS) that provides wheel-speed data. The hub is usually mounted on the suspension upright or knuckle and can be a separate bearing unit or integrated with the bearing as a hub bearing assembly.

Torque transmission occurs through the hub when the vehicle is driven. The axle delivers torque to the hub, which then transfers it to the wheel via the bearing interface and any drive splines or flanges present on the hub.

Types and scope vary by vehicle. Front hubs commonly handle steering and may be drive-capable, while rear hubs handle braking and drive duties. Disc brake hubs mount the rotor on the hub; drum brake hubs attach the drum. In bicycles, hubs are the central axle assemblies containing bearings, with configurations such as fixed, quick-release, or, on many modern bikes, a freehub for the cassette.

Maintenance involves checking for play or noise, ensuring proper lubrication, and torquing fasteners to specification. Worn hub bearings are typically replaced as a unified hub bearing assembly.

Origin: the term derives from Norwegian and other Scandinavian languages, combining “hjul” (wheel) and “nav” (hub).