Wheel bearings are something that get a lot of use, but we don’t think about very often. There are a lot of bearings in use on a vehicle, but this one gets used with every rotation of the tires. Wheel bearings generally use either roller bearings, tapered roller bearings or ball bearings to support the hub and wheel or axle shaft and wheel. This bearing allows the wheel to rotate around the axle shaft continuously and smoothly. Typically, the axle shaft runs through the inner race (or ring) and the outer race (or ring) is attached to the hub which rotates with the wheel.
Since there is a lot of movement involved, the bearing needs some type of lubrication. Depending on what the bearing is used for, it may be lubricated by oil, such as differential fluid or motor oil, or may be packed with a heavy grease. Many wheel bearings are sealed and lubricated for life, while some require periodic repacking with grease.
Wheel bearings have to carry the weight of a stopped vehicle, which is a perpendicular weight and then, when the vehicle is moving, the bearing must be able to withstand thrust and loads that are sideways to the bearing as the vehicle turns corners, etc. This combination of different kinds and directions of load and pressure places a high demand on wheel bearings, which are also subject to the same heat that brakes endure. Basically, they are going to wear out.
Worn wheel bearings are normally very noisy, and drivers will hear growling, grinding, or humming noises while driving. This noise may start with low-speed driving, and the pitch will increase as the speed increases. Turning the wheel to go around corners may make the noise worse. A worn, loose front wheel bearing can also cause vibrations in the steering wheel.
Diagnosis of a wheel bearing by a qualified technician will involve getting information from the driver about noises, or feelings of vibrations and when they are being noticed, followed by a test drive and placing the vehicle up on a lift to spin the wheels and attempt to wiggle the wheel on the hub to determine where the cause of the trouble is. Most times, this will show if the bearing is worn and now loose and no longer doing its job. Even a bearing that does not seem loose or wobbly while on the lift, may still be faulty as the bearing is not under load from the weight of the vehicle. Sometimes we can feel a bad wheel bearing in the suspension spring by lifting the vehicle and turning the wheel back and forth. Grinding sensations or noises and vibrations can still be detected while performing this procedure and are enough to determine if the bearing needs to be replaced.
Depending upon whether your vehicle is FWD or RWD and the type of bearing used and how long the vehicle has been traveling on a worn bearing doing damage to other parts, your wheel bearings may be able to be opened up, serviced and put back together or an entire assembly may have to be installed.
Give our friendly Service Representative a call today to set up a time for us to see if your wheel bearings require service.