In very simple terms, a wheel bearing is a mechanical component that enables rotational movement while at the same time carrying a load and reducing friction. A typical bearing consists of an outer race, inner race, ball or roller cage and balls or rollers. When assembled and installed in the wheel of a car or truck it enables the vehicle to move easily with a minimum of heat and maximum efficiency.
Types of bearings:
- Ball type: This type of bearing utilizes high tolerance ground metal balls, the bearing can rotate either clockwise or anti-clockwise and can deal with both radial and thrust loads. As the contact area is limited, ball bearings are normally used in applications with medium loading.
- Roller type: These types of bearings are designed to carry heavy loads. The roller is not round as the rolling member is in a ball bearing, the roller is cylindrical which means that the load bearing surface is much larger which by default means a roller type bearing can handle a far greater load. Because of the bearing design it is only suitable for radial loads, it is unsuitable to handle thrust loads.
- Tapered roller type: Rather than being a true cylinder, the rollers in a tapered bearing taper in one direction. This type is most often used as a wheel bearing as the design allows it to carry radial and thrust loads and stand up to heavy shock loads. Depending on the vehicle manufacturer, either one or two tapered roller bearings are used in wheel bearing assemblies.
Bearing components:
Other than for balls, cylinders or tapered rollers, a typical bearing assembly also has an inner and outer race and a cage that holds the rollers as well as one or two seals to keep dirt and contaminates out of the bearing as well as keeping the lubricant in.
