WHEEL BEARINGS

As wheel bearings tend to be hidden by other components, most mechanically-minded owners and drivers take them for granted, until an MOT tester advises of excessive play, or notices a tell-tale rumbling. While permitting the road wheel to rotate smoothly is an obvious function, a seized bearing can either cause the wheel to lock-up or, possibly, detach. In many cases, wheel bearings’ vital safety roles are enhanced, by becoming integrated with the anti-lockbraking and stability control systems.

Like virtually every other motorcar component, therefore, wheel bearing development has not stood still. In many cases, this has complicated the renewal procedure to the extent that you need special knowledge and tools before attempting a repair.

To find out exactly how modern vehicles differ, we have partnered with the aftermarket division of Schaeffler. This company is one of the world’s leading manufacturers of components for original fitment, working closely with vehicle producers. Wheel bearings fall under the remit of Schaeffler’s chassis-specialist brand, FAG, with an aftermarket range that is produced to Original Equipment specification and quality standards to guarantee reliability and durability.

What goes wrong?

While wheel bearings should last the lifetime of the car, abuse causes even the best-quality parts to wear prematurely. Striking kerbs, being dunked in flood water, or frequent high-speed driving over poor road surfaces can reduce bearing life. Certain modifications, such as fitting harder suspension, lower- profile tyres, or even road wheels with different dimensions to those used originally, can all place wheel bearings under extra stress.

Schaeffler highlights that incorrect fitting procedures are also a problem and Alistair Mason, the company’s technical trainer in the UK, warns that: “Wielding a large hammer and exacting brute force must never be the standard wheel bearing replacement procedure. If you are lucky, the consequences of such techniques might not be immediately noticeable but the resultant damage will cause premature failure of either the bearing itself, or the delicate internals that provide data about vehicle speed.”

THE GENERATON GAME

The demands placed upon wheel bearings have seen them evolve. Unsurprisingly, their roles in reducing rolling resistance, being more tolerant of higher forces, less maintenance intensive and quicker to install at the factory have meant that wheel bearings