An important component of any wheel is its bearings. Car wheels, skateboard wheels and motorcycle wheels all have bearings. Wheel bearings bear the brunt of the friction between the axle and the wheel so that the wheel rotation is smooth. A wheel bearing is a disk with a ball bearing inside, which rolls and enables the movement of the wheel, all the while reducing the friction. The wheel bearings must be greased and repacked regularly to function properly [source: Frantz]. If your car is vibrating or screeching, it's time to clean and grease the wheel bearings. Here's how.
- Remove the wheel bearings from your car wheel.
- Place a ball of grease in the palm of one hand. You may want to wear a pair of rubber gloves to protect your hands.
- Push the bearing into the grease with your other hand. Push in the large end first so that the grease gets forced into the inner parts of the bearing.
- Continue pushing grease into the large end, turning the bearing around so that grease comes out around the small end of the bearing.
- Spread the grease so that it covers the outside of the bearing [source: CCP].