What is the Typical Front Wheel Bearing Arrangement
Front wheel bearing design differs by vehicle manufacturer. The principles are very similar across most of the vehicle makes, and can be divided into two main groups. Bearing and race designs, and hub designs.
The bearing and race design can be found in most front wheel assemblies of rear wheel drive vehicle. Attached to the front vehicle suspension is a tapered shaft called the spindle. The rotor(Which provides your braking surface, and location of your tire mounting studs.) rides on the spindle and is supported by two sets of roller bearings. One on the back (inside) of the rotor, and the other on the front(outside) of the rotor. The bearings are tapered towards the middle of the rotor, and fit snugly to the outer diameter of the spindle. The rotor contains a smooth matched surface for the bearings to roll against called the race. Each bearing has it's own race, which is press fit into the rotor. An oil seal on the back of the rotor holds in the bearing grease, and keeps out moisture. A spindle nut and washer press against the outer bearing to hold it in place. A cotter pin inserted though a radial hole in the spindle keeps the spindle nut from coming loose.
The hub bearing design is used in many front wheel drive applications. The bearings are part of a sealed unit, and are not serviceable. The entire hub assembly must be replaced when worn. The drive axle has splines which fit into mating splines on the hub bearing assembly. An outer flange on the assembly bolts to the suspension side of the vehicle. The wheel side of the assembly holds the studs to mount your tire. With the hub mounted by it's flange, the splined end will spin when the axle rotates, thus rotating the wheel.
Both designs have their pros and cons. Roller bearings must be packed with high temperature grease. Dirt and dust can greatly shorten the life of roller bearings. Most of the contamination is introduce into the bearings during servicing. Roller bearings must be kept absolutely clean! Roller bearings must be set in place by proper torque of the spindle nut. These bearings can be tightened if need be.Hub design bearings are sealed, thus not prone to dirty repair conditions. Hub bearing assemblies can be a bit more labor intensive to service. These bearings do not need to be set for proper torque. Hub bearing assemblies are more expensive than roller bearings.
Keep it rolling!
