Since the dawn of civilisation, we humans have relied on one component to get us from A to B, the wheel. Although wheels from ancient times would be made out of rock or wood, they still did the same job as today's modern-day wheels. Some say that wheels are our greatest invention and that shows since they have been in use since their first use. The wheels you find on our vehicles today are a bit different than the wooden wheels on Roman carriages and even those in the late 19th century. They have a component called a back/ front wheel hub or assembly.

This component is what makes the wheels turn so freely and it helps make steering your vehicle safe. A wheel bearing assembly is found sitting between the brake discs or drums and drive axle. When it comes to the brake discs or drums the wheel s attached to the bolts of the wheel bearing assembly. On the side of the drive axle, the wheel hub is attached to the steering knuckle. But what does this small yet extremely important component made of?

Let's start with the front wheel assembly since it is the one that is the most engaged especially when it comes to start-stop traffic. The wheel hub is the large cast or forged metal piece that the wheel mounts to and in which the front wheel bearing assembly sits. Some hubs have integral assemblies which means you cannot replace them separately. Here the whole wheel hub is replaced even if an issue arises, let's say at the race.

Talking about the race, this component is a smooth metal ring that has both inner and outer machined surfaces. The bearings themselves are surrounded by the race which makes for the ideal surface for the bearings to rotate against. Races almost always come with a new bearing assembly but sometimes they may not be included, which is rare.

A piece of perforated metal is used to keep the bearings in place while rotating. Cages are a type of race that cradles the bearings and although they have a unique look and function they usually come together with bearings since they are still part of a front wheel assembly.

The bearing seal is a hardened rubber part that surrounds the front wheel bearing assembly so it keeps grease from leaking out. A seal also keeps water from entering the bearing assembly so it doesn't affect the operation of the bearings inside. But the seal is something that needs to be replaced often since it gets worn out. Seals are also known as bearing retainers.

Another component that helps keep other components safe is the snap ring. Unlike a bearing seal, a snap ring is made of metal and it serves as a clip. This rigid circular metal band keeps the bearing assembly and other pieces surrounding it in place. Unlike other front wheel hub components, a snap ring is easy to remove and install as you only need a specific tool that makes things a walk in the park.

While not all wheel hub assemblies have this component, an O-ing is a rubber piece that serves as the last line of defence against grease leaking from the assembly. You will mainly find O-rings on older 4x4 models as well as vans.

While grease is not a solid component it's still a crucial one for the operation of the bearings. Hub bearing assemblies use either synthetic or heavy-duty petroleum-based grease. Both of these provide lubrication so that the bearings turn easily against the surface of the race which helps make for smoother operation and minimises wear.

Grease can help prolong the lifespan of a wheel hub bearing and the higher quality grease a bearing assembly uses the longer its lifespan will be. This is why if the bearing assembly on your vehicle is removable, you need to make sure you always have enough grease into it so it works well and long enough for you to get the most out of it.

The container which you replace when there is very little grease left is called the crease packer. A bearing grease packer is usually about the size of a coffee cup. The bearing assembly sits inside of it covered in grease which makes it easier for the grease packer to keep the assembly well-fed with grease. The whole assembly is immersed into the grease with some downward pressure applied to it.

Like O-rings, dust caps are not a common part of the wheel bearing assemblies but they are an important one. Found mostly on vans and buses, a dust cap is usually made of metal coverings on the outer edge of the hub bearing assembly. As you would already assume, dust caps keep dirt and other debris out so that they don't affect the function of the assembly.