The Ultimate Guide to Wheel Bearings: Discover the Different Types
Trips to the bush often mean punctures, minor and major dents, overheating radiators and a host of things that can go wrong. Nothing that good repair and regular maintenance can’t fix. But in such punishing environments, drivers often overlook one component that literally takes all the weight – the wheel bearings. Not until they hear weird noises from the wheels and the steering starts to act up.
What are Wheel Bearings?
Wheel bearings are an essential part of the wheel assembly. Bearings are sets of steel balls or tapers held in place by a metal ring. Their job is to allow the wheels to spin freely and with minimal friction. They sit within the wheel hub and this connects the wheels to the axles.
What do Bearings do?
Bearings are tasked to take the weight of the vehicle in everyday driving. This means they bear axial and radial loads when you accelerate, turn and brake. In typical off-roading conditions, these loads are more pronounced and cars that see regular use in the bush need their bearings checked more often for signs of wear and tear. Here, debris, rocks, dust and water are more likely to eat into the bearings over time until they need to be replaced.
Types of Wheel Bearings
There are two basic types of wheel bearings – those with ball bearings and those with roller bearings. Ball bearings consist of miniature steel balls set between an inner and outer ring separated by spacers and allow for easy movement. Ball bearings are often sealed and these are better against contamination.
Roller bearings consist of rollers in differing shapes (most often cylinders) and can be in single or double rows, depending on the type of loadings the bearings need to endure. They’re often unsealed so not particularly useful in areas and uses with high pollutants.
How Long do Bearings Last?
Bearings will easily last over 150 thousand kilometres in cars driven on the tarmac. For off-roading applications, this is way less and depends on how hard you are on your rig. More technical terrain will put more pressure on the bearings and they’ll need to be replaced more often. A quality GU Patrol wheel bearing kit will keep one of Aussies’ best-loved 4WDs safe in all driving conditions. Kits for all 4WDs are available from specialised off-roading stores.
Why Bearings Fail?
Wheel bearings can fail because of a number of reasons. Where and how you drive impacts how long before the bearings need replacement. Off-roading isn’t easy on any 4WD, and here vehicles and bearings come into contact with mud, water and in desert conditions, salt. These nibble away at the seals, contaminate the grease, and corrode the bearings from the inside.
The impact from uneven surfaces and accidents damages the steel balls’ insides and reduces their ability to contain friction and heat.
Quality also plays a part. Sourcing cheaply made bearings from dubious steel means they can’t bear the weight and heat levels in more demanding use, so fail earlier. This can also cause further damage to the hubs, axles and steering. As a rule, saving a few dollars with cheaper parts will cost you more in the long run.
Incorrect fitment with the bearings, set too tight or too loose will definitely lead to premature wear. The same applies to removing the axle’s hub and bearing assembly with inappropriate tools. Kits are supplied with seals, O-rings and lock nut washers and the old ones need to be removed when installing a new set of outer and inner wheel bearings to ensure proper fit.
Changing to larger off-roading tyres is beneficial for more ground clearance, but this changes the side loading on the wheel bearings. There’s more wear on one side and bearings will fail sooner.
Signs and Symptoms of Faulty Bearings
Obvious signs that something’s not right are noises from the wheels. These could be humming or rumbling sounds when you try to turn, grinding sounds that get louder as the vehicle picks up speed, and clunking sounds over potholes, rocks and bad roads. You’ll also see that the steering is not what it used to be, as there’s a loss of feeling with the road. In addition, wear in the bearings can cause issues with braking, as the ABS sensor is located in the wheel hub.
Choosing Bearings for Your Vehicle
Larger 4WDs like the Nissan Patrol are heavy and meant to be driven in more demanding conditions. As such, when replacing faulty bearings with a GU Patrol wheel bearing kit, you’ll want these from brand name makers, and Timken, Koyo and NSK are among the more respected brands out there. The same goes for other large 4WDs like the Pathfinder, Toyota Landcruiser or Ford Everest.
Cost and Replacement
Wheel bearing kits are inexpensive (compared to other parts) and they’ll provide years of safe driving on and off-road. Replacing them involves quite a bit of work and maybe a job best left for a mechanic. First wheels and brakes come off, then the locking hub, the lock nuts and lock washers until you get to the outer bearings. Pulling off the hub will expose the inner bearings. Old seals and washers are removed, and the new bearings go in. Then there’s the task of putting everything back together.