campion bmw-a1 nat_auto woodford_ origo-2 finol autoparts-2 serfac270514a

Differences between FAG, an OE supplier and copy bearings


How long does it take for a wheel bearing to go into production after final approval from a vehicle manufacturer? Due to the extreme lengths Schaeffler goes to test its FAG branded components, both on and off the vehicle and in partnership with VM engineers, it can take anywhere between two and five years for a new bearing to be perfected, approved and fitted as original equipment.

When measured against counterfeit wheel bearings, where the materials used, design parameters, testing and consistency of this safety-critical component cannot be guaranteed, Schaeffler’s message is a simple and unwavering one, “technicians can always trust like-for-like OE replacement parts”.

Technicians fitting counterfeit or cheap copied bearings are not only jeopardising the reputation of their workshop, but they are also putting the occupants of the vehicle and other road users at risk. An OE wheel bearing is designed and manufactured to stringent VM tolerances, specifications and quality standards, and not strictly adhering to these design and engineering parameters can add additional stresses to any of the components which make-up the corner assembly of the vehicle – an incredibly dangerous scenario that must be avoided.

Fitting tips
While the technician may have the right part in the right quality, it’s also vital they know how to fit it properly. A wheel bearing is a precision part, with tolerance specifications as low as eight microns, so cleanliness is paramount. It is, therefore, extremely important to avoid any form of contamination.

Wheel bearing types can be identified by their design generation: Gen.1, Gen.2 or Gen.3. Gen.1 are just simple plain bearings, whereas Gen.2 bearings incorporate a flange which bolts to the hub, and Gen.3 are the very latest bolt-on complete ‘hub units’ with a twin flange.

Some sub-designs need special attention; Gen.2.1 bearings require a specific and precise installation procedure where the bearing must be pressed into the hub using a special tool which applies force to the outer race only. Any force applied to the inner race during this process can cause damage leading to bearing failure. The special tool clamps also correctly align and fix the bearing snap-ring into the hub, which is essential in ensuring an accurate installation. If the snap ring doesn’t ‘click’ into place in the hub recess, the bearing will slowly work its way out, eventually fouling against the CV joint.

It’s also important that technicians take extra care when installing bearings with ‘active sensor’ rings; which must be protected from damage, as the sensitive magnetic ‘teeth’ are responsible for providing the data for many safety-critical systems. Avoid laying the bearing on a workshop bench with the encoder face down, which may contaminate or damage it.

Driver at fault?
While incorrect fitting can, and most likely will, cause problems, there are other factors that can also create issues – one of which is driving style. Bearings can be damaged or wear prematurely if motorists continually fail to avoid potholes, drive their vehicle up and down kerbs, clip roundabouts or don’t drive carefully over speed-bumps: all of these avoidable scenarios can put great stress on the bearings.

Although all FAG wheel bearings undergo rigorous mud and slurry tests, no bearing can withstand contamination from deep flood water, nor are standard bearings designed for racing or rallying, which are classed as outside normal driving conditions. Technicians should warn their customers about these potential pitfalls.