Ball Bearings & Their Function on a Bicycle

Series Summary

Bicycles, or bikes--human-powered vehicles with steering mechanisms and pedals--were invented in Europe in the late 1700s or early 1800s. Though the exact history of the origins of the bicycle are somewhat ambiguous, most historians agree that the first bicycles came from France or Germany. Early bicycles appeared in many forms and operated without pedals; riders pushed along the ground with their feet. Bicycle production and refinement boomed in the 1800s, and improvements regarding ease of use and safety made the bicycle perhaps the most popular form of transportation in the world by the 20th Century. Nowadays most people take their bikes for granted, but the engineering that went into the bicycle's conception is truly fascinating.

In this free how-to video series, our expert explains how a bike is put together. He discusses the points of movement--the ball bearings, chain, cogs, wheels, spokes and tires--and he demonstrates how bicycle frames are constructed. He also discusses the materials used to build modern bikes. These instructional free video clips help us understand the parts that constitute our bicycles.

This series is an Equilibrio Films production.

Video Transcript

"Charles McMahon for Expert Village. We are talking about the bicycle. You can get more in-depth information by looking at my college level textbook and you can see that on merionmedia.com. In this segment, we are going to talk about wear resistant materials and specifically bearings, ball bearings. Now, here is where you are going to find ball bearings, on each side of the hub, there is a set of bearings. There are two sets of bearings here in the head tube. There are bearings in the pedals. There are also bearings back here in the rear hubs on each side. Now ball bearings, as you probably know are to give you very small rolling resistance to any time you have motors and anything where you get things spinning around we normally use ball bearings and the ball bearings are little balls in the seat often you have grease in there to give you extra lubrication and the bearings are hardened steel, in other words you take alloy steel raise it to a high temperature, you clench it and you temper it a little bit and you have a very hard steel and the principle in wear resistance is that you want hard materials on other hard materials, in other words they can’t squash each other because you have two metals together and you press them hard together and they start squashing, you can get what is called cold welding in little spots and then it can be ripped as you are spinning the thing, you can be ripping off little pieces from one side or the other that is how bearings or any other moving pair of metal parts fail, so you want hardened steel bearings. Now ultimately if you want the greatest kind of bearings, you use ceramic bearings because they are lighter than steel bearings and they have even much greater wear resistance, so the new thing in bearing is bearings made out of ceramics, particularly a ceramic called silicon nitrite, but in most cases the bikes are just made with hardened steel bearings as are the bearings in cars and other things. "