It’s really important to keep the wheel bearings on your vehicle in great condition. This simple-looking part does a very important job: it gives friction-free movement and rotation of the hub assembly, and thus allows your wheels to spin freely.
If a wheel bearing begins to fail, it can have serious consequences for your safety and the overall health of your vehicle.
One more thing that everyone should take into consideration is the importance of choosing the right type of grease for your wheel bearings. Generally, greasing wheel bearings is not a particularly difficult task to do yourself. Often, the trickiest part of the task is working out which grease to use. This guide will help you pick the best grease for your bearings.
Why do I need to grease my wheel bearings?
Wheel bearing grease is needed to protect these vital parts from damage and general wear and tear.
When a wheel bearing is in bad condition, there will be a lot more friction. This puts a strain on the wheel as it will not be able to turn as freely. A strain will also be put on the hub, the transmission, the axle, and the CV joint, causing unnecessary wear to these parts, too. Tires will also wear unevenly.
You may feel this wheel bearing wear and tear as ‘wheel wobble’ or a shaky steering wheel. If you listen carefully, you may also hear a grinding noise. Do note that this can be hard to distinguish from excessive road noise.
If you are observing these symptoms, you need to replace your wheel bearings straight away. Eventually, driving on badly worn bearings will cause the wheel to completely seize up. This has potentially disastrous consequences and could lead to fatalities.
Wheel bearing grease helps prevent all this. It lubricates the wheel bearings to stop parts from rubbing against each other and causing damage. Grease also protects the wheel bearings from both excessive heat and water, and this vastly improves their lifespan to their optimum range.
What is wheel bearing grease made from?
Now that we’ve established that greasing wheel bearings is an essential part of vehicle maintenance, the next step is to choose the best grease. This will provide maximum benefit to the health of your wheel bearings, provide the best protection, and help improve their lifespan.
In every wheel bearing grease, you’ll see that it’s made from a base oil and additional ingredients that include thickeners, antioxidants, anti-corrosive substances.
The base oil does the main job of lubricating the wheel bearings. However, the other ingredients can make a big difference in preventing damage and improving the lifespan of wheel bearings.
There are many greases on the market with different qualities fit particularly for specific applications considering the variety of chemical components each type contains. This can be confusing for the vehicle owner and picking one off the shelf would be more difficult.
What are the different types of grease available?
These are the three main types of automotive grease readily available. Beyond this, there are bearing greases that have various uses in industrial machinery, marine vehicles, domestic appliances, amongst others. For your car, always be sure to choose grease that states it is suitable for passenger wheel bearings.
General purpose or multi-purpose automotive grease
As the names suggest, general purpose grease is designed to work as good all-round grease with a range of possible applications for your car, making it a handy purchase. This type of grease has anti corrosion protection with excellent performance in humid environments. It performs perfectly well with temperatures ranging from -25 to 140°˚C.
Lithium-based automotive bearing grease
This grease has a high tolerance of high temperatures and good water resistance, making it ideal for wheel-bearings in most vehicles. This product is likely to provide the optimal performance you’re looking for in a wheel bearing grease, but it has limited use for other purposes.
Heavy-duty bearing grease
This high-performance grease is best suited for bearings in heavy industries involving trucks, fleets, trailers, machinery and even agricultural equipment at wide operational temperature ranges of -25°C up to 150°C.
This heavy-duty grease can be used as a multi-purpose grease but, with extreme pressure and anti-corrosion additives – which makes it more suitable and fit for arduous applications.
How to compare automotive bearing greases
Here are the main properties of wheel bearing grease that affect its performance. Use this information to make the best choice prior to purchasing.
On the container, you should find the range of temperatures at which the grease should perform well. Outside these temperatures, the grease will break down and not provide adequate protection to the bearings.
Wheel bearings must withstand high temperatures, so you are looking for grease with the widest temperature range. Greases that can sustain temperature peaks of 140°C are ideal.
You must use grease that is water-resistant. This will protect the bearings from damage, including corrosion once exposed to water.
Look for grease that has been tested for water resistance. You should see the code DIN 51 807, followed by a time and temperature (example: three hours or five days at 90°C). This indicates how long the grease was submerged for and at what temperature. There will then be a final number between 0 and 3. This indicates how much the oil deteriorated, 0 being not at all, 3 being a lot; 1 is a good result in this test for bearing greases.
Also, look for the viscosity NLGI measurement, which may also be displayed as the thickness or consistency measurement. All greases are ranked according to this scale: 000 is fluid, 0 is very soft, and 6 is very hard.
Wheel bearing greases should measure 2 or 3, which equates to something around peanut butter or vegetable shortening consistencies.
In summary, you’re probably looking for a high-quality lithium-based bearing grease that can withstand temperatures of around 140°C and with a thickness of 2 or 3. Remember to consider its water resistance as well.
Hassanein Alwan is the Managing Director of Mineral Circles Bearings with more than 10 years’ experience in the bearing industry’s technical support division, sales and marketing, plus strategic business development consultancy.