Wheel bearings

Environmental protection

Wheel bearings are designed to minimise the friction produced by the rotation of the wheels. As such they make an important contribution to fuel economy and the reduction of CO2 emissions. These are important present and future objectives for the automotive industry. Whilst the lubricant selected is a very important factor, the integration of other components associated with the wheel bearing also has an important role to play in modern bearing units. The integration of the ABS sensors, for example, and modern connections to the axle shaft reduce the weight at the axle, thereby contributing to fuel economy.

Function

Wheel bearings guide and support shafts and axles. They are part of the chassis, guide the wheels and absorb axial and radial forces. Radial forces are longitudinal forces produced as a result of rotation. They are applied to the wheel bearing at a right angle to the longitudinal axis. Axial forces, on the other hand, are forces that act on the wheel bearing in the direction of the longitudinal axis. They are produced during cornering, for example. The axial forces produced during cornering expose wheel bearings to particular stress.

Safety

Wheel bearings are components that are relevant to safety. They are responsible for stable driving behaviour and, depending on design, supply the wheel speed information for the ABS system. In the event of a fault, therefore, the ABS can also be taken out of service. If emergency braking was required, this would increase stopping distances and impair the steerability of the vehicle. 

Depreciation

Wheel bearings are designed and dimensioned to withstand high loads and high levels of environmental stress. Strong radial (e.g. caused by potholes) and axial (e.g. caused by bumping into kerbs) impacts are the biggest enemies of wheel bearings. Extreme cornering also reduces the service life of wheel bearings due to the occurrence of high axial lateral forces.

So that damage can be detected at an early stage, the garage will check wheel bearings during regular service and maintenance work.