| The bicycle can trace its history back to Germany in | | | | made of is important, because a lot of factors have to |
| the year 1817, when inventor Karl Drais developed a | | | | be taken into account: the density of the metal will |
| push bike - one without pedals. | | | | determine how heavy the bike is, the stiffness will |
| Like any other invention there were actually quite a | | | | affect the ride comfort and the control efficiency. |
| few contributors to the changing design over the | | | | There is always the danger of crashes so yield |
| years. Other inventors who contributed to the evolution | | | | strength is important - how much force will |
| of the bicycle are Scottish blacksmith Kirkpatrick | | | | permanently "deform" the metal? Also a consideration |
| MacMillan, Frenchmen Ernest Michaux and Pierre | | | | for crash-worthiness is the elongation capability of the |
| Lallement, and Englishman James Starley - whose | | | | metal. And then there's the fatigue limit and the |
| bicycle design, with the extremely large front wheel | | | | endurance limit. |
| and the extremely tiny rear wheel was called the | | | | A great many bike frames are made from steel. It's |
| "penny farthing." The "safety bicycle", with both wheels | | | | got all the best qualities needed for a frame, but its |
| the same height in a "diamond frame" that is still in use | | | | major drawback is that it is very heavy. |
| today, came into use in 1885, and in 1888 rides became | | | | Aluminum is very popular for use in bike frames, |
| much more comfortable with the invention of the | | | | because of its very low weight. But the problem with |
| "pneumatic" tire by Scotsman John Boyd Dunlop. | | | | aluminum is that it is very easy to bend it - and thus |
| Over One Hundred Years Later, Improvement | | | | break it. |
| Continues | | | | Titanium is rapidly becoming a popular material for bike |
| Just over a hundred years later, the basic design of | | | | frames. It's strong, and its light...and its very expensive. |
| the bicycle has not changed, but improvements are | | | | Only high-end bicycles are made with titanium. |
| nevertheless being made all the time. The "new age" | | | | Carbon fiber is a non-metallic material for making |
| materials now in use - aluminum, titanium and carbon | | | | bicycle frames. It is light weight, resists corrosion, and |
| fire - have enabled bicycles to be made just as sturdy | | | | can be formed into practically any shape desired. |
| as can be desired, but with the light weight which most | | | | However, carbon fiber does have low impact |
| people these days desire. | | | | resistance, so it's not so good for the mountain biker. |
| The diamond bicycle frame consists of a series of | | | | And of course it's expensive also |
| tubes: the main triangle which consists of the head | | | | Bicycle manufacturers are always experimenting with |
| tube, top tube, down tube and seat tube. The rear | | | | new materials, of course. Currently, the use of |
| triangle consists of the seat tube, paired chain stays | | | | thermoplastics is being tested, as is that of magnesium. |
| and seat stays. | | | | There's great days ahead for the evolution of bicycling, |
| What are bicycle frames made of? The metal they're | | | | so keep your helmet on and go full speed ahead! |