The Tires & Their Function on a Bicycle

Video Transcript

"Charles McMahon for Expert Village. We’re talking about the bicycle. If you want to get deeper information you can look at my college level textbook described on merionnmedia.com. So at this time we’re going to talk about tires. Now initially bicycles were made of wood, the wheels were wood and the tire on those wheels were just a strap steel, steel strap, to give it wear resistance. Later on they were solid rubber. And it was that way for a pretty long time. Then back in the late 1800s a guy named Dunlop, a Scottish veterinarian invented the pneumatic tire, so in other words a tire that is filled with air and the legend is that he did it for his daughter’s tricycle. This invention was made in about 1895 and by, I think, 1901 all bicycle tires were pneumatic tires. It only took six years to go from solid to pneumatic tires. Now you know that a tire is made out of rubber, but if that is all you had in the tire and you start pumping it up, it would act like a balloon, you just keep going and going and going. So in order to prevent that, you have to put fibers in there. Early fibers were cotton and then later on it was rayon and now you have nylon and Kevlar and so on, so you have a fabric in here and the function of the fabric is to carry the load of the air pressure, in other words to keep the thing from blowing up like a balloon. So the fibers are carrying the stress, the pressure from the air pressure inside the tire, the rubber is there to hold the fibers together to keep it from leaking. So the weight, you see the weight of the bicycle is carried by the air and the air pressure is resisted by the fibers and the rubber is there to hold the whole thing together and to give you the kind of bounce that you expect out of a tire. "