Optitec Wheel Bearing; Rear | 33416762317

Wheel bearings allow the wheels of your BMW to turn freely, even under the vehicle's weight. They consist of an inner and outer race with a ball, roller, or needle bearings set between the two, letting one race remain stationary while the other turns.

Wheel bearings fail when insufficient lubrication prevents friction between the bearings and the races. Some bearings are serviceable and require being lubricated or greased regularly to prevent premature failure. This requires the removal of the bearing and grease to be packed into the bearing cage. This process is usually performed once a year or every 15,000 miles. Seal bearings are packed with grease and have the bearings sealed between the races and do not need servicing. However, if the seal fails, the bearing will lose its grease, and the bearings and races will wear.

Wheel bearings fail in several ways, but always because of excessive friction between the bearings and races. When there is friction between the bearings and the races, it creates heat and causes either the bearings or the races to wear down. Once the bearings or races are worn down, the bearings will not turn freely, causing an audible growl from the bearing and will eventually cause the bearing to come apart. In extreme cases, the bearing can seize and no longer turn.

The most common signs of failed or failing wheel bearings are a low growling sound and vibration from the wheel when turning. Sometimes determining which wheel the sound and vibration are coming from can be difficult. Driving your BMW in a zig-zag pattern at low speed will create an additional load on each wheel individually, making the problem wheel bearing growl louder, creating a more significant vibration to help you to pinpoint which wheel bearing it is.

View more BMW Wheel Bearings.