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