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The Xtracycle Sport Utility Bicycle
Introduction While the standard bicycle is well-known as a low-cost, non-polluting mode of transportation available to most of the world’s population, its value as a utility vehicle is yet to be fully realized. The Xtracycle (Figure 1) is a fixture that can be attached to, or detached from, virtually any existing bicycle, elongating its frame and readying it for a burden. The resulting extended-wheelbase vehicle retains the simple efficiency of the bicycle while greatly increasing its effectiveness. A modular plug-in rack system makes it possible to configure the Xtracycle for hauling loads that were previously considered too long, heavy, bulky, perishable, fragile, or important to be transported by bicycle. An Xtracycle-equipped bike can haul groceries, packages, lumber, computers, passengers, water, firewood, cellos, bread, and nearly any other cargo on rugged terrain. The device will handle loads of up to 200 lbs (400 lbs with an optional heavy-duty rear wheel), while maintaining the handling characteristics of a mountain bike.
The Inspiration Many of the world’s poor have little or no means of transporting cargo other than on foot, and thus spend several hours per day carrying such loads as goods, firewood, and water on their backs—and heads. Yet many of these same people own or have access to a bicycle, a vehicle that is extremely efficient for transportation but unsuited for carrying substantial loads. One inspiration for the development of the Xtracycle, then, was to augment the bicycle’s cargo-carrying capacity, thereby freeing hundreds of millions of people from extreme physical drudgery. The challenge was to develop a device that would accomplish this task, while also being affordable to the target market. In wealthy countries (especially in Western Europe), businesses, community services, and individuals are increasingly turning to the bicycle as a means of travelling more quickly through areas gridlocked by automobile traffic. In this setting, increasing the bicycle’s load carrying capacity will enable even those who have a choice of transportation methods to use the bicycle to meet more of their needs. For example, in the gridlocked traffic typical of some urban environments, the bicycle can provide an ideal means of reaching heart attack or accident victims and stabilizing them in preparation for the arrival of an ambulance. The Xtracycle permits paramedics to carry life-saving equipment (e.g., defibrillator, oxygen, and a backboard) that will save precious minutes during the anxious wait for an ambulance making its way through heavy traffic. How the Xtracycle Works The Xtracycle is installed on a bicycle by first removing the bike’s rear wheel. Then the Xtracycle is attached to the bike’s frame at three points using quick-release bolts. Two attachment points are the dropouts where the rear wheel had been; the other is near the bottom bracket, home of the pedal crank spindle. Then the rear wheel slips into the Xtracycle’s own dropouts. A section of chain is added, brakes and derailleur are moved, and the Xtracycle is ready to haul. The conversion takes from five to thirty minutes, depending upon the particular bike. Installation is completely reversible, but it is anticipated that most users will choose to leave the Xtracycle installed, since it doesn’t detract from the bike’s rideability. Two Models Xtracycle International has developed two base frames, one intended primarily for developed countries called the FreeRadical™ (Figure 2), and another designed for developing countries, the extrabike™ (Figure 3). The FreeRadical is more modular; the engineering behind its lighter-weight construction makes it more complex to manufacture and not as well suited to small-scale production as the extrabike. The FreeRadical is primarily TIG-welded using round 4130 chromoly steel tubing with a wall thickness of 0.039 in (1 mm) in diameters of 0.75 (20 mm) and 1.0 in (25 mm), which gives it a sleeker look than the square tubing of the extrabike. However, what the extrabike lacks in modularity, it gains in versatility: with its permanent fold-down racks and solid top-frame construction, it carries a wide range of loads without modification. The Contribution of Welding For the inventor, Ross Evans, learning to weld was the genesis of the Xtracycle concept. Even more importantly, the ability to weld prototypes for user testing led to rapid advancement of the design, and to significant innovations. He has taught the skill of welding to farmers in Nicaragua and fishermen in Senegal, recognizing the true empowerment of people as they see the implications of their ability to weld. As Rafael Solis, a trainee in Managua, Nicaragua, exclaimed, "Now I can make anything!" (Figure 4) The advent of small, inexpensive, portable MIG welders has aided the design, growth and spread of the Xtracycle concept around the world. Although stick welding can be used to fabricate the square-tubed extrabike model, Xtracycle International recommends the use of portable MIG welders for their low cost, ease of use and quality finish. In flying overseas to teach workshops, the authors have found it optimal to stow a Lincoln SP-125 Plus in the overhead bin of the airplane. They are often working in village settings where electricity is rationed to only a few hours a day. Therefore, the ability of workers to plug in an SP-125 Plus and become immediately productive is an important asset. Ross Evans also invented a square tube bending machine that is easy to replicate in a low-tech environment from parts readily available in scrap metal yards. Bent square tubing is not commonly seen, and people in the third world find it very attractive. Markets The product addresses the needs of two distinct groups. First, it enables people with no alternative to foot and bicycle transportation to carry substantial cargo loads that would otherwise be immensely time-consuming, unwieldy, or impossible to manage. While there are only about 4 million cargo bikes in the world (including pedicabs), in developing countries alone there are an estimated 500 million bicycles that, using the Xtracycle, could be converted to carry cargo. The world’s rural poor, especially women, often spend up to half their waking hours carrying water, firewood, and food. In many cases, both time expended and physical hardship could be significantly reduced with the use of a cargo bike. The Xtracycle could also enable the creation of small businesses such as parcel couriers and delivery services. Second, the Xtracycle permits an alternative even for those with access to an automobile. Forty percent of all vehicle trips in the United States are two miles or shorter, and more than twenty-five percent are less than a mile. Many of these trips could be taken using an Xtracycle to carry whatever load might be necessary, from groceries to surfboards. In the developed world, the product fills a void between large, cumbersome utility tricycles and small, ineffective racks and bags. Significance of Results The Xtracycle marries low cost and high performance in a unique and easy-to-manufacture product. Its introduction has led numerous small communities in the developing world to discover the value of welded design. In addition, the small scale sale of locally produced Xtracycles has become a revenue source for many artisans and mechanics, providing an economic incentive to open small welding shops. For further information, see: www.xtracycle.com
This
project has been published to show how individuals used their ingenuity
for their own needs, convenience and enjoyment. Only limited details are
available and the projects have NOT been engineered by the Lincoln Electric
Company. Therefore, when you use the ideas for projects of your own, you
must develop your own details and plans and the safety and performance
of your work is your responsibility.
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©1999-2008 The Lincoln Electric Company. |
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