by Lance Wright
The hub and bearing assembly is attached to the spindle and steering knuckle of a vehicle’s front suspension. The hub and bearings provide a rotation point for the wheel, as well as support for the weight of the vehicle on the spindle or axle. Rear wheel drive vehicles use tapered roller bearings for the front wheels. The wheel bearings are placed in the hub with the tapered ends facing one another. The inner bearing is larger than the outer bearing due to the need for increased support for the wheel. The outer races of the wheel bearings are pressed into the hub assembly. The wheel bearings are lubricated with bearing grease and are completely serviceable. Bearing preload (the tightness) is set with the hub retaining nut. The hub retaining nut is secured to the spindle and torqued to a specified setting and is secured using a cotter pin.
Front wheel drive vehicles generally use sealed roller bearings pressed into the hub. These bearings are usually only serviced as an assembly and since they are sealed, require no maintenance. Some front wheel drive bearing designs use tapered roller bearing assemblies. This type of wheel hub design is generally a press fit and bearing preload is set using spacers.
owned his own auto repair shop for 30 years before retiring in 2006.)