Your car's wheels do not run directly on the axle; they rotate on a wheel bearing, which is usually made from high-grade steel balls that rotate between two pieces of steel called races. Some wheel bearings are made up of small high-grade steel rods that rotate between two tapered steel races. Bearings reduce rolling friction and allow your vehicle to roll easily on the road. Wheel bearings that run within brake rotor discs are sealed and self-contain their lubrication while those that run in drums are usually the taper type and are open to the elements.

Bearing size chartpdf

If your car begins to emit a grinding noise at low speeds which turns into a low drone at higher speed which emanates from one of the wheels, the bearing may have collapsed. If you experience shuddering through the steering wheel during braking or turning, the wheel bearing may have collapsed. An easy check is to grab the tyre and shake the wheel vigorously side to side, if the wheel rocks, then it is highly likely that the bearing has failed.

We delve into the fascinating world of the bearing to gain some insight into these friction-beating devices and how to know if you need to replace yours.

Bearingnumber andsize chartpdf

Replacing a wheel bearing requires heavy-duty garage equipment that you generally won't have at home. A hydraulic press is needed to push the races out of and off of the hubs, as these are very tightly press-fitted. Attempting to remove and replace a wheel bearing without a press will damage the new bearing. This is not a cheap exercise as there is a lot of labour involved. The bearings themselves are not expensive and usually cost a few hundred rand, but it is the labour cost that could easily push a wheel bearing replacement into the thousands. Depending on the vehicle model, it may even be cheaper to buy a completely new hub and knuckle assembly that can just be changed out as a complete unit.

BearingID ODchart

Your car's wheels, too, have bearings, and if these should fail, you will find out rather quickly that something is wrong. We take a look at these interesting pieces of engineering, and how to know, and what you can do if they stop working properly.

Bearings are designed to last the maximum amount of time if they operate in ideal conditions, with sufficient lubrication. A bearing will begin to break down and fail if the lubrication is removed or contaminated with water or dirt or if they overheat. Bearings also have a lifespan measured in operational hours, but this lifespan will be reduced significantly if rust or dirt contaminates the races or overheating occurs.

Modern automobiles are made up of hundreds of thousands of parts but it cannot be argued that the most important of those are the contact points with the road. Your wheels, tyres, brakes, and suspension system are critical in keeping your car on the road. There are hundreds of friction points on a car, and in the most critical points, engineers will install bearings to keep that friction to a minimum and help propel the vehicle forward with as much ease as possible.

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