The most common types of bearings are wheel bearings. Motorcycle wheels have them, so do skateboards. The bearings help give you a smooth ride.
Proper maintenance of the ball bearings is the key to ensuring they do not give you any problems. Bad bearings usually are the causes of the clunking noises you hear as you turn the wheel, or the gritty feel on the wheel. If you're wondering what these wheel bearings look like, you might have actually seen them in your broken bicycle or if you have tried to repair your wheels. Most types conceal the balls in these bearings. These balls are made of special alloys of stainless steel.
It was no less than Renaissance man himself, Leonardo Da Vinci who described a type of wheel bearing in his studies in the beginning of the 16th century. The invention of the wheel bearing, alongside the otherventions of the rebirth, is one of the most significant heirlooms of the era that have changed little over time. Leonardo da Vinci is said to have described a type of wheel bearing around the year 1500.
One issues with ball bearings is that they can rub against each other, causing additional friction, but this can be prevented by placing the balls in a cage and heavy lubricate them.
To find a good lubricant, take a look at the back of the can and make sure that they are made of proper oils that will not destroy the metal of your wheel bearing. The bearings tend to wear over time, and you can not really do anything about it but to replace them. It is advised that you find the same quality, as some lesser quality wheel bearings may not keep up with your original ball bearings, and you may end up ruining your skateboard or motorcycle wheels.