Pub. 6 2016 Issue 1

21 MINING FOCUS so that the rear wheel will be free from the crank mechanism if the rider isn’t pedaling. To attach the wheel to the frame, manufacturers use an axle that runs through the wheel’s hub. The axle can be tightened using bolts on the end or skewers that have a quick release. What is the future of the bicycle? Computers have made it possible to make improvements that will guarantee their continued popularity. Recumbent bikes are more aerodynamic than conventional ones, can be safer, and sometimes offer protection from the weather and room to carry cargo. A Dutch surgeon named Wim Van Wijnen designed a hybrid car and bicycle called the Ecocar that has been available in Europe since the 1990s. No matter the form, biking will continue to be a popular mode of transportation well into the future. The next time you ride your bike and feel the wind in your hair, recall that feeling of freedom you had as a child. And don’t forget to thank a miner for making it possible. The following image can be found at http://goo.gl/jK08AL The frame consists of the front and rear triangles, the front really forming more of a quadrilateral of four tubes: the top, seat, down, and head tubes. The rear triangle consists of the chainstays, seatstays, and rear wheel dropouts. At- tached to the head tube at the front of the frame are the fork and steering tube. Read more: http://goo.gl/OuudjE. X the center of the tube can be thinner because it undergoes less stress. To make a seamed tube, the manufacturer starts with a flat steel strip stock, wraps it to make a tube, and then welds it. Carbon was used to create structural fiber composites in the 1990s. These composites are designed to be strongest along the fiber’s axis and they can be shaped into frames consisting of a single piece. Plastic binders or glue are used to join the composites. Stainless steel is still used to build brakes, chains, derailleurs, and wheels. Gear shift levers to control the derailleurs can be mounted in three separate places: racing bikes usually have them on the down tube, but they can also be on the stem or the handlebar. A cable connects the gear shift levers to the front and rear derailleurs. Manufacturers clamp or braze the front derailleurs, which is located on the seat tube. They use bolt-on hangers or integral hangers to mount the rear derailleurs. Handlebars can be dropped, flat, or raised. Manufacturers bolt them to a bicycle stem that fits into the head tube. The headset is attached to the head tube. It allows a rider to turn the fork inside the head tube while steering. Components include bearings, cups, and locknuts. Brake levers are generally on the handlebars. Cables connect the brake levers and the brakes; the cables are fastened to calipers on the brakes. Manufacturers attach plastic or cloth tape to the handlebars and plug the ends. Seat posts can be made of steel or aluminum alloy. Manufacturers bolt or clamp them in place. Most saddles used to be covered by leather, but it is now more common to see molded padding covered with nylon or plastic materials. Cranksets provide support to the pedals and transfer power from the pedals to the rear wheel through the chain. They consist of several parts: crank arms made from aluminum alloy or steel, chain rings, and a bracket assembly on the bottom that has an axle, cups, and bearings. They are fastened onto the bike with bolts and caps that are on the bottom bracket of a bicycle frame. Pedals are attached to the ends of the crank arms. Wheels are usually built by machine. The process involves making hoops from rolled steel strips, then welding the hoops into rims. By drilling the rims it is possible to attach the spokes. These are laced individually between the hub flange and the rim. Once the wheel has been straightened radially and laterally, which creates uniform tension, the rim liner, the tire, and the inner tube can be attached and the chain can be fitted. Manufacturers fit rear wheels with cogs and spacers World Bicycle and Automobile Production, 1950-2007 Source: Worldwatch; Bike Europe; Global Insight Bicycles Cars Million Units Top tube Head tube Seat tube Seat Stay Down tube Chain stay The most important part of the bicycle is the diamond-shaped frame, which links the components such as wheels, derailleurs, brakes, and chains together. Rear wheel dropouts Fork/ fork blade