Wheel Hub Assembly
A structural unit that attaches the wheel to the vehicle, containing the wheel bearings, wheel studs, and wheel speed sensors.
The wheel hub assembly (or hub unit) is a critical drivetrain component that connects the wheel to the vehicle's suspension and steering systems. Located between the brake rotors and the drive axle, it holds the wheel studs that secure the wheel and tire, and houses the wheel bearing that allows the wheel to spin smoothly.
In modern vehicles, the wheel hub assembly is often a single, pre-sealed unit that includes the hub flange, high-precision bearings, and a built-in anti-lock brake system (ABS) wheel speed sensor. This integrated design simplifies assembly and improves component longevity, but requires replacing the entire unit if the bearing or ABS sensor fails.
Worn wheel bearings inside the hub assembly will cause a loud, deep roaring, humming, or grinding sound that increases with vehicle speed. A failing ABS sensor inside the hub will illuminate the ABS warning light and disable traction control. Play in the hub assembly can also cause steering wheel shimmy or loose handling.
Replacing a wheel hub assembly requires removing the wheel, brake caliper, and rotor to access the mounting bolts. Proper torque specifications must be followed during installation to prevent premature bearing failure.