BICYCLING

Bicycling is a simple, affordable, and energy-efficient means of transportation. Of all human-powered locomotion, it is the fastest and least energy-demanding.

The bicycle has stunning efficiency advantages over other vehicles for several reasons:

• It weighs roughly one-fifth of its payload weight. (By comparison, even a small motorcycle weighs more than the rider.)
• With the exception of avid sport and competitive use, it is typically operated at low speeds that do not cause high aerodynamic drag.
• Its internal mechanical efficiency can be nearly perfect —a 1999 test at Johns Hopkins University showed chain efficiencies as high as 98.6 percent — and energy losses due to rolling resistance are far less than for other vehicles.

The light weight and mechanical efficiency not only allow the bicycle to be powered by a nonathletic human, but it can be walked over extreme terrain, or laden with heavy cargo, or picked up and carried. These options make the bicycle more versatile than any other vehicle, and allow a bicycle user door-to-door, on-demand transport.

For any given speed, the energy demands are close to half that of running, and 15 to 20 percent that of ice skating or roller skating. Moreover, better bikes, better techniques, and better athletes continually help set new speed and endurance records. The record speeds accomplished with recumbent two-wheeled bikes enclosed in an aerodynamic shield have surpassed 110 kilometers per hour (68 miles per hour). The record distance that cyclists can cover in an hour on an unfaired (no separate process to make-it more aerodynamic), upright bike has risen from 35 kilometers (21.7 miles) in the 1890s to over 51 kilo-meters (31.7 miles) in the 1990s.

The bicycle's energy efficiency superiority extends beyond human locomotion and beyond all other forms of transportation. By converting food into the energy equivalent of gasoline, the kilocalories of food energy needed by a human to pedal a bicycle is only a fraction of that needed to propel planes, trains, and automobiles (see Table 1).

HISTORY

Bicycles have been around since the early part of the nineteenth century. In 1817 Karl Von Drais invented a walking machine to get around the royal gardens faster. Made entirely of wood, the rider straddled two same-size, in-line wheels, steering with the front wheel and locomoting by pushing against the ground. This steerable hobby horse, which could surpass runners and horse-drawn carriages, never became a viable transportation option because of the need for smooth pathways, which were rare at that time.

A second major effort at self-propelled transportation came when Pierre Michaux invented in 1861 the velocipede ("fast foot") that applied pedals directly to the front wheel. To achieve greater speed with every pedal revolution, designers tried larger and larger front wheels, with some reaching almost two meters in diameter. Despite garnering interest from hobbyists, the velocipede had three major deficiencies as transportation: First, lacking gears, it was difficult to climb even a modest grade; second, because the construction was entirely of wood, with metal tires coming slightly later, the cobblestone roads of the day made for an extremely uncomfortable ride; third, the big front wheel created problems. Riding was extremely dangerous and inaccessible to most women and children.

A fresh start and the true beginning of bicycles becoming a popular means of transportation can be traced to around 1886 and the efforts of John Kemp Starley and William Sutton. With equal-sized wheels, tubular steel diamond-shaped frame geometry, and a chain-and-sprocket chain drive to the rear wheel, the "safety bike" looked much like the modern version.

During the late 1890s, bicycles were the worldwide focus of invention and technical innovation, much as biotech engineering and computers are today. We owe many of today's industrial manufacturing processes, designs for bearings, axles, and gearing mechanisms, and the knowledge of lightweight structures, to the explosion of inventions that bicycles produced.

In the United States, England, and other major nations, patents were awarded at the rate of about 5,000 per year per nation. In one peak year, bicycle-related patents comprised close to one-third of all patent-writing activity. Many of these patents were decades ahead of the technology to manufacture them; for example, suspension systems invented a century ago became viable only with modern-day elastic materials and manufacturing technology.

The two most important single inventions of this long-ago era were Starley's tension-spoked wheel and John Dunlop's pneumatic tire. The tension-spoked wheel was and is a marvel of lightweight structures; it allows four ounces of spokes, on a wheel weighing a total of three or four pounds, to support a 200-pound rider. (Today's carbon fiber wheels have yet to show a clear advantage over the wheel made from humble carbon steel spokes.) The pneumatic tire, which Dunlop invented in 1888, vastly improved the bike's comfort, and it also shielded the lightweight working mechanisms from excess vibration and fatigue. The coaster brake appeared in 1889, and it has been a staple of children's bikes ever since.

Because a bicycle uses a low-power engine (the rider) and because that rider can only apply power only over a small rpm range, gearing is essential to match the rider's output to the riding conditions. The first patent for bicycle gears was granted in France in 1868; the rider pedaled forward for one gear and backward for the other gear.

An 1869 patent by France's Barberon and Meunier foresaw today's derailleurs. It described a mechanism that would shift a belt or chain sideways among three sprockets or discs. That same year, Barberon and Meunier also patented a primitive gear hub.

These technical innovations dramatically improved performance. Bicycles of that era were hand-made in cottage industries, and were highly sought after and expensive. So impassioned were their owners that the League of American Wheelmen, founded in 1880, was for several years around the turn of the century the strongest political lobby in the United States, with a membership in the hundreds of thousands. The League's "Good Roads Movement" was the first political movement to lobby for a network of high-quality, paved roads throughout the nation.

Between the development of the chain-drive bicycle in the 1880s, and before Henry Ford popularized the automobile in the 1910s and 1920s, bicycling was extremely popular as an efficient means to quickly get around. It was over three times as fast as walking, and more convenient and cheaper than having a horse-drawn carriage at one's disposal. Unfortunately, the quickly improving performance, reliability and affordability of the automobile made it a formidable competitor to the bicycle.

The automobile ascended to dominance in North America starting in the 1920s, and in Europe by the 1950s. After World War II, most nonauto ground transport in the United States rapidly disappeared. The decades following World War II saw vast reductions in train travel, bus service, and public transportation systems in major cities.

The shift to personal autos was slower in many European countries, where many of the population could not afford autos, and where the governments placed very high taxes on gasoline and automobiles. Bicycles, motorcycles and public transportation continued to be widely used in these countries. In addition to the economic factor, there was a cultural reason for Europe's slower embrace of the automobile. Europeans have long lived with high population density within finite borders. The United States of the 1940s was a far more rural nation, with sprawling farmland inside the borders of major cities. That autos took up lots of space in a city was an obvious drawback to the European mind, but irrelevant in Texas.

The poorer nations of the planet had no choice, and used bicycles and public transportation exclusively. For example, when China was under Mao Tse Tung's rule, the number of private automobiles was only in the hundreds.

Beginning in the 1970s, the bicycle saw a resurgence of interest in North America. Reasons included environmental concerns with the internal combustion engine, the popularity of bicycling as a multifaceted sport (racing, touring, mountain-bike riding, family cycling), the desire for fitness, and the need for alternative ways of commuting in crowded cities.

Bicycling to work is viewed as the most environmentally friendly means of travel, the best way to avoid congested roadways (in some cases, it turns out to be quicker than mass transit or driving), and a means of turning commuting time to exercise time. The bicycle is far more efficient than the automobile in making good use of city streets. Traffic counts taken during the 1980 New York City transit strike showed that a single street lane devoted to bicycles could carry six to eight times the number of people per hour than as a lane for auto traffic.

During these past few decades, the bicycle itself has vastly improved. The bicycles of the early 1970s usually had mechanical idiosyncrasies. Competition among manufacturers, led by the Japanese companies that entered the U.S. market, resulted in vastly improved quality control. The mountain bike, first made available on a widespread basis in 1983, offered a delightful alternative that mushroomed in popularity, and a decade later, traditional "road" bicycles had all but disappeared from stores. The mountain bike has become most people's vehicle of choice for city riding as well as recreational trail riding.

It has also helped that the bicycle buyer is continually offered more bicycle for less money. No longer are most bikes steel. While steel continues to be a fine material, the dominant material reported by bike enthusiast is now aluminum, which, in the hands of most designers, yields a lighter but more rigid frame. Well-heeled bicyclists opt for titanium or carbon-fiber composites.

There has also been a huge improvement in the value of today's mountain bikes. A mountain bike in the $300 to $500 price range typically has a suspension fork and aluminum frame that would have made it a $1,500 bike a decade earlier. The $800 dual-suspension bike of 2000 far outclasses the early 1990s $2,500 offering.

THE HUMAN ENGINE

The bicycle's advantages as the world's most mechanically efficient means of transportation are clouded by the limitations of the human engine. To put it in power output terms, the human body can produce sustained power only at modest levels. For most people, 100 watts would be too much, and for an elite athlete, 400 watts is the approximate ceiling. (The athlete may manage a brief burst of 1.1 kilowatts.)

The lower power output is inevitable because a body cannot long produce more power than it can simultaneously convert from the chemical mixing of blood glucose and oxygen (aerobic exercise). The higher brief bursts of power do not rely on real-time glucose/oxygen consumption, which is why the athlete is out of breath for minutes afterwards. The athlete's muscles have "borrowed" the results of future oxygen and glucose consumption in anaerobic exercise. For long-distance travel, yet another limitation appears: the body stores about a two-hour supply of glucose. After that glucose is exhausted, the body has to revert to the far less desirable mechanism of burning fat. The muscles produce less power with fat than they do with glucose, and only a trained endurance athlete can comfortably exercise beyond the glucose barrier into the fat-burning zone.

When the automobile became preeminent in the early twentieth century, it did so with good reason. Whether the energy to power a bicycle is anaerobic or aerobic in nature, it is still minuscule in comparison to what an automobile's internal combustion engine can deliver. In the United States, almost all subcompact cars are equipped with engines that can generate 100 or more horsepower (74,600 watts), and can sustain this output all day long.

The human engine cannot match this power output, yet the mechanical efficiency of the bicycle helps tremendously because a very small amount of horsepower can generate great speed. For example, 0.4 horsepower (298 watts) of output can result in 25 mph (40 kph) speeds or better. One set of calculations shows that if a cyclist rode on level ground, with no rolling resistance, and aided by a 25 mph tailwind, it would require only around 0.2 horsepower (150 watts) to sustain a 25 mph pace.

Gravitational Resistance

If not for the need to climb steep hills, bicycling at a 15 mph (24 kph) clip would never be a strenuous exercise. It takes approximately 82 watts, or 0.11 horsepower, on an efficient bicycle, to ride 15 mph on flat ground. But ground is seldom flat. That same 82 watts achieves only 8 mph climbing a barely discernible two percent grade. A five percent grade slows one down to just over 4 mph. Most riders don't want to slow down that much, so they work harder to maintain some speed. On descents, they work less hard, while going still faster.

Any weight reduction helps. Gravitational forces do not discriminate between bike and rider mass, but the human body does. If one spends an extra thousand dollars to shave ten pounds off a bike, there will be a 10-pound advantage, but if one sheds the 10 pounds from the belly, the body will not have to nurture those ten pounds of living tissue, and one will be a more efficient engine.

Air Resistance

Air resistance is a greater factor than most people realize. Even at 10 mph on flat ground, almost half the rider's energy goes to overcoming wind resistance. Rolling resistance is almost nil at the speed. At 15 mph, two thirds of the energy is need to overcome wind resistance. At 25 mph, about 85 percent of the rider's energy is devoted to overcoming wind resistance, with the remainder overcoming rolling resistance and the tiny frictional losses within the bicycle itself. So sensitive is the wind resistance to the rider's aerodynamic profile that riders who race time trials at these speeds feel the bike slow down dramatically if they sit up to take a drink from their water bottles.

For these reasons, most riders cannot, or will not, increase their speed much above their personal comfort levels, even with lots of training. The additional speed just costs the rider too much energy. A rider going 15 mph must double his power output to ride 20 mph. Why these dramatic numbers? Wind resistance varies with the square of the rider's airspeed, but the energy to overcome wind resistance increases with the cube of the rider's airspeed.

Of course, the air is rarely still, just as the ground is rarely flat. Tailwinds do speed the rider, but headwinds have a direct effect on the rider's speed, too: A rider traveling at 20 mph into a 15 mph (24 kph) headwind encounters as much air resistance as a rider traveling at 35 mph (56 kph) under windless conditions. A headwind will slow one down by half its own speed. If one normally rides 15 mph, and then steers into a 10 mph headwind, the resulting speed will be 10 mph.

Because of the significant increase in drag a rider encounters as speed is increased, small adjustments of bike and body contours can significantly alter energy expenditures. These alterations can be to clothing, frame design, handlebars, wheels (spokes), rider profile, and the race strategy of drafting. Of the two resistance factors, the rider and the bike, the rider accounts for approximately 70 percent of the wind resistance encountered, while the bicycle accounts for only 30 percent. Unlike a sleek automobile, the high upright bike and rider is a very inefficient aerodynamic profile, so encircling a rider and bike fully or partially in a streamlined fairing can drop the drag coefficient by 0.25, resulting in a top speed increase from 30 to 36 mph (48 to 58 kph). However, this gain could be somewhat negated on hot days because of the body overheating, or from instability caused by gusty crosswinds.

Fully faired bicycles and faired adult tricycles are today the stuff of cutting edge inventors and hobbyists. Virtually all of them are recumbent bikes, because it makes sense to start out with a smaller frontal area to begin with. Some are reasonably practical for daily use, with lights, radios and ventilation systems; others are pure race machines.

Rolling Resistance

Rolling resistance is almost directly proportional to the total weight on the tires. It is the sum of the deformation of the wheel, tire, and road surface at the point of contact. Energy loss occurs when the three do not return all of the energy to the cycle.

Rolling resistance varies tremendously by tire. Greater air pressure and less contact area is the reason the rolling resistance that a tops of-the-line racing tire encounters on smooth pavement is half or one-third that of a heavily-knobbed mountain bike tire.

But unlike air resistance, rolling resistance varies directly with speed, which means that as speed increases, the rolling resistance factor becomes less important relative to the air resistance. A bike going 20 mph has twice the rolling resistance of a bike going 10 mph. If the bike has good-quality tires with proper inflation pressure, neither rolling resistance number is high enough to be particularly significant.

Rolling resistance declines with smoother and harder road surfaces, larger diameter wheels, higher tire pressures, smoother and thinner tread, and narrower tires. In the case of rough, pot-holed roads, energy is lost in bounce. For soft surfaces such as gravel or sand, energy is robbed and absorbed by the surface. Anyone who has ridden with severely under-inflated tires or through mud can attest to the extremely wasteful loss of human energy.

Over rough surfaces, an opposite effect, not easily measured in the laboratory, becomes apparent to the rider. A tire inflated to very high pressures (for example, 120 pounds) bounces off the peaks of the road surface, making the bike harder to control, and negating any theoretical decrease in rolling resistance. For that reason, top racers often use moderate inflation pressures (85 to 90 pounds). Studies have found that superinflatable tires (120 to 140 pounds) offer no noticeable advantage over high-inflation tires because they do not appreciably decrease rolling resistance.

Wheel size can have as dramatic an effect on rolling resistance as tire inflation. On paper, a smaller wheel size has more rolling resistance, a rougher ride, and poorer handling over bumps than a larger wheel size. Rolling resistance is inversely proportional to the radius of the cylinder, that is, given the same conditions, smaller-wheel bikes experience more resistance to motion than larger-wheel bikes.

Fortunately for the makers of small-wheel folding bikes, several factors can mitigate these shortcomings, such as by using wider tires to compensate for the smaller diameter. The use of improved modern tire technology and the use of suspension in combination with small wheels also help. In modern times, the father of small-wheel suspension bikes, Alex Moulton, began designing these bikes in the 1950s, and his most recent designs have taken this bicycle type to a new level. Hot on the heels of the Moulton bicycle are bicycles such as Germany's sophisticated dual-suspension Birde. Many riders believe these bikes completely negate the alleged disadvantages of small-diameter wheels.

Pedal Cadence

Numerous physiological studies have addressed the optimum pedal cadence, but these studies usually miss the point because they focus on the seemingly important factor of efficiency.

Efficiency is measured in power output per oxygen consumed. However, the rider's supply of oxygen is, for all practical purposes, unlimited, and most riders do not pedal at an effort level that leaves them constantly breathless. Even if they did, they would not want to follow the results of efficiency studies. These studies consistently show that recreational cyclists produce the best sustained performances (lowest metabolic rate and highest efficiency) when the seat is raised 4 or 5 centimeters above the normal height, the pedal cranks are slightly longer to make it possible to use higher gears, and the pedal cadence is in the 40 to 70 rpm range. However, experienced riders, whether fast or slow, virtually always choose to ride differently than the studies recommend.

Why? Efficiency does not matter if one has unlimited oxygen. What does matter is long-term comfort. Pedaling at the rate shown to be most efficient uses up blood glucose the fastest. This leaves the rider more susceptible to that sudden loss of energy known as "the bonk," and it also tends to leave more lactic acid and other waste products in the muscles, increasing discomfort and extending recovery time.

By contrast, pedaling faster (90 to 100 rpm) in a lower gear at a lower effort level allows the body to burn some fat along with the glucose, thereby extending the glucose reserves. The more rapid leg motion promotes blood circulation, the better to remove waste products from the muscles. This faster cadence is undeniably less efficient, because the body uses energy just to spin the legs around, but it results in increased long-term comfort.

Novice cyclists will often prefer the "more efficient" slower cadence and higher saddle because this configuration uses the leg muscles in a manner more similar to the way walking uses those muscles. In addition, the novice cyclist is often unable to benefit from a higher pedal cadence because of an inability to apply force perpendicular to the crank, resulting in excessive body motion. A bike rider needs to gain some experience with the "less efficient" faster cadence so his/her muscles develop the coordination to function smoothly in this new discipline. Having done that, the rider is unlikely to go back to the slower, less efficient way.

Cleated shoes and toeclips are also advocated on efficiency grounds. Every world-class cyclist uses toeclips today because studies have shown significant aerobic and anaerobic benefits. Toe clips often give elite riders a false sense of power production during the stroke recovery phase. Elite riders feel that toeclips double their deliverable pedal power —a coordinated push-pull effort, exerting an upward force, with the trailing leg alongside the downward force of the forward leg. In reality, however, the cadence is too fast to create a pulling-up force. The importance of cleated shoes and toe clips is in their ability to stabilize the foot and more effectively generate a pushing force rather than in generating a pulling force during the recovery stage. Recreational cyclists benefit from this foot stabilization as much as elite cyclists, do but many of them are uncomfortable with toe clips. Moreover, toe clips are undeniably clumsy in the frequent start/stop environment of crowded city traffic.

Alternative Propulsion Systems

Throughout the history of the bicycle, inventors have questioned whether the century-old circular sprocket design is the most efficient. Many inventors have built elliptical chainwheels, usually to have a "higher gear" during the power stroke and a "lower gear" during the dead spots at the very top and bottom of the pedal stroke. Numerous studies show that even elite riders are unable to apply propulsive force to the pedals during these portions of the power stroke, much as they are unable to lift on the backside of the power stroke.

These elliptical chainwheels have never been widely popular. Sophisticated cyclists tend to shun them because cyclist develop a riding rhythm and a comfort pattern from years of experience. Novices do not even know they exist. Most bike designers fear that elliptical chainwheels would tend to make novice cyclists less inclined to develop a smooth pedaling style.

During the 1980s, Japan's Shimano Corporation invented a radically different alternative to round chainwheels. The development of Shimano Biopace chainwheels began with a very sophisticated study of the biomechanical performance of bicyclists, and Shimano discovered two flaws that it wanted to correct. The first flaw was that the leg was speeding downward as the foot approached the 6 o'clock (bottom) position, and this downward momentum of the leg mass was not being harnessed and converted into forward motion. The second flaw occured during the upstroke phase of the pedal path. Shimano discovered that at this point in the pedal path, the knee joint was switching from flexion to extension, and the switch was so fast that both sets of muscles were being energized at once —so that the body was fighting itself.

Shimano addressed the first problem with a design that seemed counterintuitive. The chainwheel was shaped so that the rider experienced the feeling of a lower gear during the power stroke. Then, at the bottom of the pedal stroke, the gear got higher, to absorb the energy from the leg mass's downward momentum (see Figure 1). The second problem was addressed by a change in the chainwheel shape, which slowed down that portion of the pedal stroke, giving the leg a few additional hundredths of a second to switch between flexion and extension.

As good as Shimano's research was, the product bombed in the notoriously conservative bicycle marketplace, and Biopace is history today. It's doubtful that bicycles will ever come with nonround chain-wheels. The round ones do too good a job, and are too easy to make and market.

Lever propulsion —requiring an up-and-down stair-climbing motion —is another propulsion system long proposed, on efficiency grounds, as a replacement for the standard pedal-and-crank system. Though promising in theory, studies have shown that the muscle efficiency for pedaling a chain wheel is not inferior to that associated with stepping and steep-grade walking. Lever systems maximize the problem of harnessing the leg mass's downward momentum, and work against the smoothness that experienced riders have come to enjoy so much.

There is no basis for the theory that only when pushing the whole stroke vertically do the muscles work efficiently, and that the backward-and-forward foot movement over the top and bottom wastes energy. Certainly, there is some efficiency loss, but it is minimal. Toe clips and better variable gear systems have further minimized "top-dead-center problems" associated with the standard circular sprocket design.

THE BICYCLE AS TRANSPORTATION

Bicycles are the number-one mode of transportation in the world. More than 100 million new bicycles enter the market each year and, in Southeast Asia alone, around 700 million bicycles are used daily as a means of transportation.

China is the world's biggest producer and user of bicycles. Since 1985, China has been manufacturing more than 30 million bicycles each year. In Shanghai, more than 4 million people bicycle to work and school every day. Bicycles far outnumber automobiles. Whereas there is one automobile for every 1.7 people in the United States, in China there is only about one automobile for every 680 people. However, the developing nations seem determined to become overdependent on the automobile as well. In the quest for greater status and mobility, motorized vehicles are quickly becoming the most sought-after possessions in Asia and other developing nations. This pro-auto movement quickens with economic growth that creates more capital to purchase the vehicles. Paying for the energy to run the vehicle is a much smaller concern. As a larger segment of the Asian population rapidly becomes affluent and develops an addiction to the automobile —similar to that is the United States and other developed nations — world petroleum consumption will soar. The U.S. Department of Energy projects Asian transportation petroleum demand will nearly triple from 1995 to 2020, going from 9.6 to 26 quadrillion Btu's.

Although the bicycle is primarily used for recreation in North America, some urban areas (e.g., San Francisco, New York, and Toronto) are experiencing an upswing in the number of workers commuting by bicycle instead of car. Widespread use of bicycles for commuting would have a profound effect on energy supplies and society. If half of the U.S. labor force biked to work instead of driving, the United States could significantly curtail petroleum imports; moreover, the exercise attained by pedaling to work could shrink the obesity and overweight population, and thereby dramatically improve the overall health of many. Despite these benefits, a massive switch to bicycling is highly unlikely for one major reason: It is impractical. There are too many inconveniences involved that are simply unacceptable to the majority of an increasingly affluent population, particularly when the alternative is a climate-controlled, high-speed drive to work in a very comfortable automobile.

The primary inconvenience is the relative slowness and lack of comfort, especially during days of inclement weather. Many millions of Americans live great distances from where they work. Some might consider bicycling five miles to work each day, but few live that near to work. The typical 20-or-30-mile commute makes bicycling an unrealistic option for most people. And for those who do live close to work, few are willing to brave the elements to bicycle year around. Rain, snow, ice, high winds, extreme cold, and extreme heat that are minor inconveniences in a vehicle become major inconveniences on a bicycle. Thus, for backup, bicycle riders usually must own a vehicle for bad weather days, or have access to convenient mass transit.

By contrast, the bicycle survives as basic transportation in the Netherlands and Germany because those nations have a social infrastructure built to make it possible. Those countries have a neighbor-hood-centered way of life, and the trip distances on a bicycle are often two or three kilometers or less. People cycle slowly out of politeness to others on the crowded streets. Public transit is also far better than in the United States. It is amusing to see a German commuter train station with virtually no auto parking available, but hundreds of bike parking spots.

Intermodal commuting with a bicycle may someday be a way around congested roadways. One of the biggest problems facing mass transit developers is trying to provide service to a sprawling, residential community that needs to commute to equally decentralized work sites. The majority of the population resides a driving distance from mass transit stops, and mass transit service ends too far from a work site to make walking practical. If buses and trains were equipped to carry bicycles, or folding bicycles gained wider acceptance, the bicycle might someday serve as the intermodal link. The bike could be pedaled to the train, loaded for mass transit, and then pedaled the final leg of the commute. It is uncertain whether this alternative means of commuting will ever become attractive enought to overcome the drawbacks of weather, bicycle storage, and safety concerns.

Some people believe that bicyclists require dedicated bike lanes and trails. This is a half-truth. Certainly, these facilities are widespread in Germany and the Netherlands, but they are far less common in other cycling countries such as the United Kingdom, France, and Cuba. In those countries, bicyclists have long known that they can share the road with automobiles as long as all road users respect the same set of rules.

Dedicated facilities are often cited for safety purposes, but this, too, is not a simple truth. Most accidents occur at intersections, and dedicated facilities make intersections far more complex. When the Netherlands allowed their moped riders to travel in the auto lanes instead of the bike lanes, the moped accident rate fell by an astounding 70 percent. The bicycle accident rate would be higher if bicyclists tried to ride at brisk speed in these separated bike lanes. The sub-10-mph speeds that are considered polite in these countries largely allow bicyclists to compensate for the facilities' shortcomings, at the expense of travel time.

In the United States, advocates for bicycling are divided on the question of special facilities. It is doubtful that Dutch-style facilities would create much greater ridership in most U.S. locales, because the trip distances are too long. The best reading of accident statistics shows that adult riders well-schooled in sharing the road with automobiles and respecting the same rules ("vehicular cycling") have about one-fifth the accident rate of a control group of otherwise-well-educated adults.

Aside from the comfort and convenience disadvantages of bicycling, perhaps the biggest obstacle is the price of energy. Energy is far too cheap to make pedal power worthwhile, except as a hobby. For most people, the cost of the one or two gallons of gasoline used commuting each day is paid for in less than 10 minutes of work time. Of course, the pedal power equivalent of electrical energy is even less. To travel at 15 mph (24 kph) on flat ground requires only around 82 watts of power. If one ran on electrical energy instead of food energy, the cost of the electricity to generate that 82 watts to travel 14 miles to work is about 0.7 cent.

Sweating is another problem. Few people want to arrive at work with a sweat-soaked body. There are usually no showers at work, and few want the additional burden of lugging work clothes that would need pressing on arrival. For most riders, sweating is inevitable, particularly when climbing hills. The human body is about one-third efficient in converting the energy of glucose into muscle movement. The other two-thirds is waste heat, and sweat is how the body gets rid of excess heat.

Because of the desire to avoid perspiring, and the limited energy available to propel a bicycle, there is growing interest in electric motor-assisted bicycles that can make that 15-mile commute to work a near-effortless experience. The electric motor allows the rider to maintain a reasonable speed without exerting enough energy to perspire. The U.S. market saw at least a dozen brands of electric-assist bicycle during the 1990s. The more sophisticated offer regenerative braking 15 to 20 miles of range, and recharging cost of 2 to 3 cents for a 15-mile distance (at 10 cents kWh).

These bikes could be a wonderful transportation option, combining the efficiency, quiet and nonpollution of a bicycle with the ease of riding a small motorcycle. For these reasons, electric-assist bikes sell at the rate of over 200,000 per year in Japan. But in the United States, these bikes run up against a cultural barrier. Bicycle enthusiasts, who are less likely to object to their four-figure price tags, do not want a motor and do not want a bike that weighs 60 pounds. Others do not want to be seen riding to work. So U.S. sales have been poor. As the number of motor scooters and motorcycles in Asia has grown at an alarming rate, policies to encourage the use of electricity-assisted bicycles are seriously being considered as a way to curtail vehicle emissions. In Bangkok, Thailand alone, over one million people needed treatment for smog-related respiratory problems in 1990. Greater affluence and the demand for faster transportation in China have resulted in yearly sales of motorcycles increasing from less than half a million sold in 1991 to over 10 million by 1996, further contributing to air pollution that is already some of the worst in the world. Unless zero-emission transportation, such as electric bicycles, gains in popularity, the number and severity of smog-related respiratory problems are certain to worsen in the most densely populated urban areas of Asia.

John Schubert John Zunerchik

See also: Aerodynamics; Biological Energy Use, Cellular Processes of; Culture and Energy Usage; Flywheels.

BIBLIOGRAPHY

Allen, J. S. (1981). The Complete Book of Bicycle Commuting.Emmaus, PA: Rodale Press.

Cross, K. D. (1977). A Study of Bicycle/Motor-Vehicle Accidents: Identification of Problem Types and Countermeasure Approaches.Santa Barbara, CA: Anacapa Sciences.

Faria, I., and Cavanaugh, P. (1978). The Physiology and Biomechanics of Cycling.New York: Wiley.

Forester, J. (1994). Bicycle Transportation.Cambridge, MA: MIT Press.

Hunt, R. (1989). "Bicycles in the Physics Lab." Physics Teacher 27:160 –165.

Romer, R. (1976). The Energy Fact Book. Amherst, MA: Department of Physics, Amherst College.

Schubert, J. (1988). Cycling for Fitness.New York: Random House. Whitt, F., and Wilson, D. (1974). Bicycle Science.Cambridge, MA: MIT Press.

BICYCLING

The German agriculturist Karl von Drais is generally acknowledged as the "father of the bicycle." His idea for a wooden, two-wheeled, running machine, which he patented in 1818, was soon copied by inventors in America. In 1819, "hobbyhorses" made their appearance on the streets of Boston and New York, and laws were quickly promulgated to prohibit their use on sidewalks. The novelty of these cumbersome forms of locomotion soon wore off, until the inventive spirit of the Industrial Revolution sparked new ideas in transport, leading to three major boom periods for cycling in America.

The initial craze for cycling began in the 1860s with the invention of the velocipede, a cast-iron machine with pedal cranks attached to the front wheel. The development of this "boneshaker" created a new mode of transport and industry, fostering different forms of sporting and recreational activities. Although velocipedes were originally popularized in France, transatlantic trade ensured intense competition in its manufacture and marketing. The velocipede craze peaked in America around 1869, when nearly every major city built at least one rink for the machine. However, new patents and fierce rivalries for profits continued to drive improvements to the velocipede.

The Cycling "Craze"

The next boom period—the late 1870s, and early 1880s—saw the advent of the high-wheeler, also known as the "ordinary" or "penny farthing." The first ordinary appeared at the 1876 Centennial Exhibition in Pennsylvania. Entrepreneur colonel Albert Pope of Boston soon began manufacturing these novel machines and, with control of patents and aggressive marketing, he became known as the "father of American bicycling." Advertising posters for the Pope Manufacturing Company show that the sleek, superior, and relatively cheap high-wheeler quickly superseded the heavy and expensive velocipede. Many of the basic elements present in the modern bicycle, including ball bearings, tangent-spoked wheels, and hollow steel tubing, were introduced at this time. In 1878, the Boston Bicycle Club signaled the beginning of cycling clubs, introducing some people to a whole new way of life. Young males in particular enjoyed not only the inherent camaraderie of the group, but also the collective protection from unprovoked harassment aimed at lone cyclists.

The League of American Wheelmen (LAW), formed in 1880 with just forty-four members at Newport, Rhode Island, reflected this upsurge in popularity. Membership grew from almost 12,000 in 1894 to more than 141,000 cyclists in 1898. This group promoted numerous cycling activities, including touring and racing, and was a strong advocate for better roads and legislation. Most cycling enthusiasts were located in the eastern states, particularly Massachusetts and Connecticut.

Competitive cycling became highly popular and usually occurred in connection with other athletic sports. Considerable prize money was offered, generating a much-publicized and fierce quest for speed by "scorchers," growth in professionalism, and the consequent involvement of bookmakers. Racing became increasingly formalized, and, in 1886, the American Cyclists Union was created to help regulate the sport. A number of American track stars achieved notable success overseas, including Arthur Zimmerman, nicknamed "The Flying Yankee," and Major Taylor, an African American whose remarkable and controversial career was "marked by his speed, his skin color [in what was then a white-dominated sport], and his religious convictions" (Perry, p. 364).

Bicycle touring also became popular, with numerous trans-American trips and world tours undertaken by groups of cyclists as well as individuals. Noteworthy was American Thomas Stevens, who achieved the first overland circuit of the globe on a high-wheeler between 1884 and 1887. Women also rode remarkably long distances. For example, in July 1894, Mrs. E. Witchie became the first woman in the Midwest to cover a hundred miles in one day.

Cyclists met with considerable opposition, particularly by people using horse-drawn transport. Newspapers commented that it seemed as if all America were divided into two classes—those who rode bicycles and those who did not. The more individualistic activity of cycling diverted many young males from more established team sports and recreations. This new leisure pursuit, accompanied by a proliferation of bicycle-riding schools, marketing of cycling accessories, and publication of numerous books and magazines, thus presented a challenge to the popularity of customary recreational activities.

The breakthrough that ensured the continued popularity of the bicycle was the pneumatic tire. While the concept of an air-filled tire had its beginnings in Scotland in 1845, it was 1888 before Scotsman John Dunlop designed a tire suitable for use on the "safety" bicycle, developed in the mid-1880s. The pneumatic tire was introduced into America in 1890, and the burgeoning cycling industry received a noticeable boost as buyers clamored for the mechanically superior and safer machines. Consequently, long-standing objections to women cycling were swept aside. The widespread popularity and availability of the safety bicycle thus created the third, and biggest, boom for cycling throughout the industrialized world. Initially more expensive than the solid-tired high-wheeler, sales of safety bicycles quickly overtook those of the "ordinary" and bicycle production increased markedly.

Women's Cycling in the Nineteenth Century

In the late nineteenth century, the bicycle gave middle-class women independence and social freedom, but not without controversy. Compared to a horse and carriage, the machines were more economical to maintain and run and easier to manage, and they required no special clothing, equipment, accommodation, or staff. With her own bicycle, a woman was able to determine where and when she would ride. Social criticism, however, focused on the masculinity of the new activity—it was unfeminine to ride and to wear cycling clothes, and it made respectable women conspicuous in public.

Logistically, shopping and visiting became more straightforward, but the bicycle also opened up new recreational and sporting opportunities. Group rides and activities were a regular feature of the cycling season, and the club environment enhanced women's knowledge of bicycles and cycling techniques. Clubs also introduced young females to a wider social network, affording favorable occasions for meeting and mixing with young men, sometimes on tandems, without the expected chaperone. Excursions were a major attraction of cycling. In addition to day or weekend trips, major cycle tours appealed to the more adventurous woman, who explored not only her city or state, but also nationally and internationally. Cycle racing offered a new sporting opportunity for competitive women, and American riders won international acclaim. Both track and road racing were highly popular with audiences throughout the 1890s, partly because of the spectacle of women in scant clothing. Women's racing was rarely taken seriously, however, and declined until a gradual revival in the 1930s.

For some women, cycling symbolized the principles of self-determination and social equality and offered the perfect opportunity to promote issues such as dress reform, female suffrage, and temperance, as well as the more general idea of women's social progress. Riding a bicycle necessitated changes in attitudes toward fashion, for dangerous clothing, as well as comfort and convenience, were mutual concerns of cyclists and dress reformers alike. Bloomers, named after Amelia Bloomer, an ardent supporter of dress reform, were promoted in earlier decades, but with limited success. It was not until the bicycle boom of the 1890s that dress reform cyclists readily adopted bloomers.

Popular Culture and Bicycling

During the 1890s, the bicycle, including the tandem, became a feature in songs, poems, jokes, pictures, and literature, many of which often had a romantic theme. In 1892, Henry Dacre published the now-famous song, "Daisy Bell."

Daisy, Daisy,

Give me your answer do,

I'm half crazy

All for the love for you!

It won't be a stylish marriage,

I can't afford a carriage

But you'll look sweet upon the seat

Of a bicycle built for two.

Early to Mid-Twentieth Century

Prices of new cycles continued to fall from 1895 onward. With the ever-increasing secondhand market, and the easily available installment purchase schemes, cycling remained a popular pursuit, despite competition from the automobile. But, unlike in Britain and Europe, in America the period spanning World War I was characterized by a steady decline in cycling. Colonel Pope had turned to automobile manufacture. Cycling generally came in a poor second to the attraction of the motorcar and, according to McGurn, also suffered competition from new electric mass transportation systems. Children's cycles continued to appeal, but it was only the gasoline shortages of the 1940s that caused another brief, but significant, demand for bicycles. After World War II, Americans, like the British and Europeans, sought relief from wartime austerity by enthusiastically engaging in recreation activities. Sports stadiums, cinemas, holiday camps, and seaside resorts were immensely popular, but the pursuit of leisure increasingly involved the acquisition of consumer goods and use of the motorcar, all to the apparent detriment of cycling.

Revival of Bicycling

In the latter decades of the twentieth century there was a marked revival of cycling, stimulated both by market differentiation and environmental and health concerns. During the 1960s, American manufacturers were developing lighter-weight models with the adolescent market in mind. The twenty-six-inch wheel size distinguished these bicycles from the smaller-wheeled children's models and sold well. For the younger set, the Raleigh "chopper," or "high-rise" cycle, with its ape-hanger handlebars, curved "banana" seat, and raised frame behind the seat, was launched in 1969, marking the first of the action bicycles that subsequently evolved. Over time, the "high-rise" design incorporated derailleur gears (used to shift the chain from sprocket to sprocket to change gears, especially in multigeared bicycles, where very low gearing enabled easy hill climbing) and hand brakes and then led to the more sophisticated ten-speed models that dominated the 1970s. This was a highly profitable period for the cycle industry, signified by what cycle historian Frank Berto calls the "Great American Bike Boom of 1971–1974." Conventional wisdom states that this American boom was caused by the oil shortage and recession that followed the Arab-Israeli war, but Berto disagrees, pointing out that the war began in late 1973 and, by the end of that year, the shortage was over. The bicycle boom, nearing its end at this stage, was extended mainly because of public perceptions of the energy crisis. Notwithstanding, bicycling grew steadily into the 1980s and beyond.

Market differentiation gave potential riders a vast array of options, playing on the desire for novelty, adventure, and identity. Image became a key feature of new designs, which were aimed at teenagers. The increasing sophistication of the ten-speed, with its inverted curved handlebars and sleek appearance, appealed to the now-adult post-chopper riders, bolstered by the strong popular interest in health and fitness that marked the late 1970s. The BMX (bicycle motorcross) machine, which enabled riders to negotiate offroad dirt tracks, and to perform stunts, soon replaced the chopper. In the mid-1970s, the mountain bike began its evolution. The first widely available models were the "Specialized Stump Jumper," by San Jose company Specialized Bicycle Imports, and the Univega Alpina Pro, by Long Beach company Univega. Both models were manufactured in Japan. Throughout the 1980s, mountain bike designs were highly popular, and by the mid-1980s, sales of these machines had exceeded road bikes. Mountain bikes differed from road bikes in several key ways: They had wide, knobby tires instead of skinny smooth tires; handlebars were usually upright instead of the inverted curved handlebars; and the frame, seat, and wheels were designed to handle rough terrain comfortably.

Aggressive tourism marketing in the 1990s helped to swell the number of riders who explored their local environs and farther afield. In the early 2000s, a network of creative designers continued to develop new and innovative designs to cater to all cycling needs, including riders with disabilities. A small group of designers produced various recumbent (more horizontal, with the rider sitting low to the ground with legs extended to the front) designs for comfort and energy efficiency, as well as folding cycles for carriage on public transport. Even more enterprising individuals designed bicycles equipped with computers and global positioning systems for long-distance touring.

Frances Willard

Frances Willard (1839–1898) was well-known in the United States and abroad for her social reform efforts. She served as president of the Women's Christian Temperance Union (WCTU) from 1879 until her death in 1898, building it into the largest women's organization of its time, and founded the World WCTU. She learned to ride a bicycle when aged 53 years. She called her bicycle "Gladys" on account of the "exhilarating motion of the machine, and the gladdening effect of its acquaintance and use."

Networks of Enthusiasts

A number of key American organizations actively promote cycling. The League of American Bicyclists (LAB) encourages bicycling for fun, fitness, and transportation, and works through advocacy and education for a bicycle-friendly society. Originally the League of American Wheelmen, it was responsible for improving terrible road surfaces and helping to establish the current national highway system through its Good Roads movement. Another important organization is the Bicycle Federation of America (BFA), a national, nonprofit corporation established in 1977 to create bicycle-friendly and walkable communities. Now operating as the National Center for Bicycling and Walking (NCBW), its major focus is greater involvement of the public health sector in transportation policy and land-use planning to help create more physically active communities. The passage of the Intermodal Surface Transportation Efficiency Act (ISTEA) in 1991 has provided tangible support for numerous bicycle projects that has resulted in significant increases in cycling numbers and, concurrently, decreases in cycle-related fatalities. The 1997 report "Share the Road" stressed the importance of continued cash flow from ISTEA's funding framework and planning provisions.

A conference in 2000 brought together for the first time a diverse group of bicycle advocates, injury prevention specialists, and government representatives. The resulting "National Strategies for Advancing Bicycle Safety" was the first step in changing the cycling environment in significant ways. The National Bicycle Safety Network (NBSN)—a public-private coalition of federal and state agencies, professional and nonprofit safety groups, and bicycling advocacy organizations—volunteered to facilitate implementation of activities for selected portions of the strategy. Similarly, Probicycle, a key advocacy group that promotes education and safety and the skills of effective advocacy, has the motto "Same Roads, Same Rights, Same Rules." Children's participation in cycling was also a key concern of cycle advocacy. Parents and teachers were encouraged to teach sound cycling skills, road rules, and the wisdom of wearing a helmet.

The Father of American Bicycling

Colonel Albert Pope became known as the "father of American bicycling." An 1880 advertising poster for his firm, the Pope Manufacturing Company, promoted the superiority of the bicycle over horse-drawn transport. The advantages of the durable and speedy high-wheeler are highlighted, as well as the need for cycling accessories.

In the early 2000s, cycling was integral to community health policies and programs. Physical activity, combined with overeating, steadily increased the incidence of overweight or obese adults from 47 percent in 1976, to 56 percent in 1994, and 61 percent in 1999. For children and adolescents, the prevalence doubled during the same period (Wilkinson et al., p. 2). The 2001 Surgeon General's report stressed the importance of physical activity in reducing these and other lifestyle diseases and ailments, and, in response, the National Center for Bicycling and Walking published a guide for public health practitioners in which it advanced the argument that more people would bicycle more often if they had safer places to ride.

A wide array of cycling organizations in America cater to specific interest groups, aside from traditional racing. Cyclo-cross, for example, is the cycling equivalent of cross-country running. The sport originated in Europe around seventy-five years ago as an off-season training option as well as to develop advanced riding skills. Cyclists ride on forest trails, parks, and fields, carrying their bikes over unridable sections such as streams and fallen trees. The sport is well developed in the United States, with numerous clubs staging local events.

The American Bicycle Association (ABA) was created in the late 1970s to administer what is now known as BMX, an activity with an enormous following. Similarly, in response to the immense interest in mountain biking in the 1980s, the International Mountain Bike Association (IMBA) was formed. Since 1988, IMBA has encouraged environmentally sound and socially responsible low-impact riding, volunteer trail building, cooperation among different trail-user groups, and more.

Cycle Routes and Trails

Cycle routes and trails are popular with riders, not only because of their high safety record but also because of their aesthetic appeal. Although dedicated routes are a safe alternative to sharing roads or pathways, many communities lack paths that are separate from road traffic. Trails are also popular. Some examples of the hundreds of successful trails that now exist include the Burke-Gilman Trail in Seattle, Washington; the Eliza Furnace Trail in Pittsburgh, Pennsylvania; and the Riverfront Trail in Missoula, Montana. For longer rides, cyclists can access trails fostered by the Rails-to-Trails Conservancy, which aims to enrich America's communities by creating a nationwide network of public trails out of former rail lines and connecting corridors. Besides riding rail trails, cycle tourists can take advantage of the hundreds of groups now organizing extensive tours within America. The NCBW calls for more trails to be built, not only because they are safer for cyclists but also because they encourage more people to take up cycling, thereby increasing community fitness and health.

Bloomers

These loose fitting trousers were adapted from harem pants and first worn by members of the New York Oneida Community in 1848. Bloomers were worn in public around 1851, and popularized by Elizabeth Smith Miller, but named for her friend Amelia Bloomer, editor of the reform journal, Lily. Bloomer supported their use in order to free women from the cumbersome long skirts of the day. Short-lived in popularity, their use was revived during the bicycle boom of the 1890s.

Conclusion

While precursors of the bicycle can be traced back to the Renaissance, it was only during the nineteenth century that advances in technology and design throughout Europe and the United States resulted in the modern form of the machine. Cycling rapidly gained popularity not only as a means of transport, but also as a leisure pursuit and sporting activity for both men and women. The bicycle became the fastest mode of self-propelled locomotion, and the sensation of speed, a completely novel feeling, became one of the pleasures of cycling. Cycling remains an immensely popular leisure activity for Americans of all ages, and the bicycle remains the epitome of an urban machine. While the bicycle has represented the benefits of technological progress and typified the refinements of civilized existence, according to Richard Harmond and others, it has also been the means of escape from a tension-prone industrialized society. On this basis, the activity of cycling will continue to be an emotional palliative for many of today's urban problems.

See also: Automobiles and Leisure, Commercialization of Leisure, Progressive-Era Leisure and Recreation, Tourism, Urbanization of Leisure

BIBLIOGRAPHY

Beeley, Serena. A History of Bicycles. London: Studio Editions, 1992.

Berto, Frank J. "The Great American Bike Boom." Rivendell Reader no. 19 (Spring 2002): 12–17.

Cohen, Brian, Richard Wiles, Chistopher Campbell, Bill Wilkinson, and James Corless. Share the Road: Let's Make America Bicycle Friendly. Washington D.C.: Environmental Working Group/The Tides Center, 1997.

Dunham, Norman L. "The Bicycle Era in American History." Ph.D. diss., Harvard University, 1956.

Harmond, Richard. "Progress and Flight: An Interpretation of the American Cycle Craze of the 1890s." Journal of Social History 5, no. 2 (1971–1972): 235–257.

Herilihy, David V. "The Velocipede Craze in Maine." In Cycle History: Proceedings of the 8th International Cycle History Conference. Edited by Nicholas Oddy and Rob van der Plas. San Francisco: Van der Plas Publications, 1998.

McGurn, Jim. On Your Bicycle: The Illustrated Story of Cycling, 2d ed. New York: Open Road Publishers, 1999.

Norcliffe, Glen. The Ride to Modernity: The Bicycle in Canada, 1869.–1900. Toronto: University of Toronto Press, 2001.

Perry, David B. Bike Cult: The Ultimate Guide to Human-Powered Vehicles. New York: Four Walls Eight Windows,1995.

Smith, Robert A. A Social History of the Bicycle. New York: American Heritage Press, 1972.

Wilkinson, W. C., N. Eddy, G. MacFadden, and B. Burgess. Increasing Physical Activity Through Community Design. Washington: National Center for Bicycling and Walking, 2002.

Willard, Frances E. How I Learned to Ride the Bicycle: Reflections of an Influential 19th Century Woman. Edited by Carol O'Hare, with an introduction by Edith Mayo. Sunnyvale, Calif.: Fair Oaks Publishing, 1991.

Clare Simpson and Rob Hess

Bicycle

Background

Bicycles are one of the world's most popular modes of transportation, with some 800 million bicycles outnumbering cars by two to one. Bicycles are also the most energy-efficient vehicle—a cyclist burns about 35 calories per mile (22 calories per km), while an automobile burns 1,860 calories per mile (1,156 calories per km). Bicycles are used not only for transportation, but for fitness, competition, and touring as well. They come in myriad shapes and styles, including racing bikes, all-terrain bikes, and stationary bicycles, as well as unicycles, tricycles, and tandems.

History

As far back as 1490, Leonardo da Vinci had envisioned a machine remarkably similar to the modern bicycle. Unfortunately, da Vinci did not attempt to build the vehicle, nor were his sketches discovered until the 1960s. In the late 1700s a Frenchman named Comte de Sivrac invented the Celerifere, a crude wooden hobby horse made of two wheels and joined by a beam. The rider would sit atop the beam and propel the contraption by pushing his or her feet against the ground.

In 1816 the German Baron Karl von Drais devised a steerable hobby horse, and within a few years, hobby-horse riding was a fashionable pastime in Europe. Riders also discovered that they could ride the device with their feet off the ground without losing their balance. And so, in 1840, a Scottish black-smith named Kirkpatrick Macmillan made a two-wheel device that was operated by a treadle. Two years later he traveled as many as 40 miles (64 km) at a stretch during a record 140-mile (225 km) round trip to Glasgow. A couple decades later, a Frenchman, Ernest Michaux, designed a hobby horse that utilized cranks and rotating pedals connected to the front axle. The Velocipede, made with wooden wheels and an iron frame and tires, won the nickname of the "boneshaker."

The 1860s proved to be an important decade for bicycle improvements with the inventions of ball-bearing hubs, metal-spoked wheels, solid rubber tires, and a lever-operated, four-speed gearshift. Around 1866 an unusual version of the Velocipede was created in England by James Stanley. It was called the Ordinary, or Penny Farthing, and it had a large front wheel and a small rear wheel. The Ordinaries were soon exported to the U.S. where a company began to manufacture them as well. These bicycles weighed a hefty 70 pounds (32 kg) and cost $300—a substantial sum at the time.

By 1885, another Englishman, John Kemp Starley, created the Rover Safety, so called since it was safer than the Ordinary which tended to cartwheel the rider over the large front wheel at abrupt stops. The Safety had equally sized wheels made of solid rubber, a chain-driven rear wheel, and diamond-shaped frame. Other important developments in the 1800s included the use of John Boyd Dunlop's pneumatic tires, which had air-filled inner tubes that provided shock absorption. Coaster brakes were developed in 1898, and shortly thereafter freewheeling made biking easier by allowing the wheels to continue to spin without pedaling.

During the 1890s bicycles became very popular, and the basic elements of the modern bicycle were already in place. In the first half of the 20th century, stronger steel alloys allowed thinner frame tubing which made the bicycles lighter and faster. Derailleur gears were also developed, allowing smoother riding. After the Second World War, bicycle popularity slipped as automobiles flourished, but rebounded in the 1970s during the oil crisis. About that time, mountain bikes were invented by two Californians, Charlie Kelly and Gary Fisher, who combined the wide tires of the older balloontire bikes with the lightweight technology of racing bikes. Within 20 years, mountain bikes became more popular than racing bikes. Soon hybrids of the two styles combined the virtues of each.

The Raw Materials

The most important part of the bicycle is the diamond-shaped frame, which links the components together in the proper geometric configuration. The frame provides strength and rigidity to the bicycle and largely determines the handling of the bicycle. 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. Attached to the head tube at the front of the frame are the fork and steering tube.

For much of the bicycle's history the frame was constructed of heavy, but strong, steel and alloy steel. Frame material was continually improved to increase strength, rigidity, lightness, and durability. The 1970s ushered in a new generation of more versatile alloy steels which could be welded mechanically, thereby increasing the availability of light and inexpensive frames. In the following decade lightweight aluminum frames became the popular choice. The strongest metals, however, are steel and titanium with life-expectancy spanning decades, while aluminum may fatigue within three to five years.

Advances in technology by the 1990s led to the use of even lighter and stronger frames made of composites of structural fibers such as carbon. Composite materials, unlike metals, are anisotropic; that is, they are strongest along the axis of the fibers. Thus, composites can be shaped into single-piece frames, providing strength where needed.

The components, such as wheels, derailleurs, brakes, and chains, are usually made of stainless steel. These components are generally made elsewhere and purchased by the bicycle manufacturer.

The Manufacturing
Process

Seamless frame tubes are constructed from solid blocks of steel that are pierced and "drawn" into tubes through several stages. These are usually superior to seamed tubes, which are made by drawing flat steel strip stock, wrapping it into a tube, and welding it together along the length of the tube. Seamless tubes may then be further manipulated to increase their strength and decrease their weight by butting, or altering the thickness of the tube walls. Butting involves increasing the thickness of the walls at the joints, or ends of the tube, where the most stress is delivered, and thinning the walls at the center of the tube, where there is relatively little stress. Butted tubing also improves the resiliency of the frame. Butted tubes may be single-butted, with one end thicker; double-butted, with both ends thicker than the center; triple-butted, with different thicknesses at either end; and quad-butted, similar to a triple, but with the center thinning towards the middle. Constant thickness tubes, however, are also appropriate for certain bikes.

The tubes are assembled into a frame by hand-brazing or welding by machine, the former being a more labor-intensive process and therefore more expensive. Composites may be joined with strong glue or plastic binders. The components are generally manufactured by machine and may be attached to the frame by hand or machine. Final adjustments are made by skilled bicycle builders.

Assembling the Frame

Tailoring the tubes

• 1 The metal is annealed, or softened by heating, and hollowed out to form "hollows," or "blooms." These are heated again, pickled in acid to remove scale, and lubricated.
• 2 The hollows are measured, cut, and precision mitered to the appropriate dimensions. Frame sizes for adult bicycles generally run from 19-25 inches (48-63 cm) from the top of the seat post tube to the middle of the crank hanger.
• 3 Next, the hollows are fitted over a mandrel, or rod, attached to a draw bench. To achieve the right gauge, the hollows pass through dies which stretch them into thinner and longer tubes, a process called cold drawing.
• 4 The tubes may be shaped and tapered into a variety of designs and lengths. The taper-gauge fork blades may have to pass through more than a dozen operations to achieve the correct strength, weight, and resilience.

Brazing, welding, and gluing

• 5 Tubes can be joined into a frame either by hand or machine. Frames may be brazed, welded, or glued, with or without lugs, which are the metal sleeves joining two or more tubes at a joint. Brazing is essentially welding at a temperature of about 1600°F (871°C) or lower. Gas burners are arranged evenly around the lugs which are heated, forming a white flux that melts and cleans the surface, preparing it for brazing. The brazing filler is generally brass (copper-zinc alloy) or silver, which melt at lower temperatures than the tubes being joined. The filler is applied and as it melts, it flows around the joint, sealing it.

Aligning and cleaning

• 6 The assembled frames are placed into jigs and checked for proper alignment. Adjustments are made while the frame is still hot and malleable.
• 7 The excess flux and brazing metals are cleaned off by pickling in acid solutions and by washing and grinding the brazing until it is smooth.
• 8 After the metals have cooled, further precision alignments are made.

Finishing

• 9 The frames are painted, not only to create a more finished appearance, but also to protect the frame. The frame is first primed with an undercoat and then painted with a colored enamel. Paint may be applied by hand-spraying or by passing the frames through automatic electrostatic spraying rooms. The negatively charged frames attract the positively charged paint spray as the frames rotate for full coverage. Finally, transfers and lacquer are applied to the frame. Chrome plating may also be used instead of paint on components such as the fork blades.

Assembling the
Components

Derailleurs and gear shift levers

• 10 Depending on the style of bicycle, the gear shift levers are mounted either on the down tube—popular on racing bikes—on the stem, or on the handlebar ends. A cable is attached, which extends to the front and rear derailleurs. Front derailleurs, which move the chain from one drive sprocket to another, may be clamped or brazed onto the seat tube. Rear derailleurs may be mounted with bolt-on hangers or integral hangers.

Handlebars, stems, and headsets

• 11 Handlebars may be raised, flat, or I dropped. They are bolted to the bicycle stem which is then fitted into the head tube. The headset components, including bearings, cups, and locknuts, are attached to the head tube. The headset allows the fork to turn inside the head tube and thus makes steering easier.

Brakes

• 12 The brake levers are mounted to the handlebars. Cables extend to the brakes and are fastened to the calipers. Tape, made of plastic or cloth, can then be attached to the handlebars and the ends are plugged.

Saddles and seat posts

• 13 Seat posts are generally steel or aluminum alloy and are bolted or clamped into position. The saddle is generally made of molded padding and covered with nylon or plastic materials. Although leather was the norm for saddles for a long time, it is less commonly used today.

Cranksets

• 14 The crankset supports the pedals and transfers power from the pedals to the chain and rear wheel. Cranksets consist of steel or aluminum alloy crank arms, chain rings, and the bottom bracket assembly of axle, cups, and bearings. They are attached with bolts and caps into the bottom bracket of the bicycle frame. The pedals are then screwed to the ends of the crank arms.

Wheels, tires, and hubs

• 15 Wheel manufacturers conform to the A J International Standards Organization (ISO) system for wheel diameter and tire sizes. Wheels may be constructed by machines, which roll steel strips into hoops that are welded into rims. The rims are drilled to accept spokes, which are laced one round at a time between the rim and hub flange.
• 16 A wheel must be trued, or straightened, in radial and lateral directions to achieve uniform tension. Next, the rim liner, tire, and inner tube are attached. The chain may also be fitted onto the bicycle.
• 17 Rear wheels are fitted with a free-/ wheel, consisting of several cogs and spacers, which frees the rear wheel from the crank mechanism when the rider stops pedaling.
• 18 Wheels are attached to the bicycle frame by means of an axle which runs through the hub of the wheel. The axle may be tightened with bolts at the ends or with quick-release skewers.

The Future

The future for bicycles looks promising as we approach the 20th century. Developments in bicycle technology in the 1990s have led to advances in human-powered vehicles (HPVs) design. Most HPVs are low-slung recumbents, which are more aerodynamic than conventional bicycles and therefore reduce drag and increase speed. Recumbents are also safer, and many provide cargo room and weather protection. A hybrid of the bicycle and automobile called the Ecocar began to surface on European streets by the 1990s. Designed by a Dutch surgeon, Wim Van Wijnen, it provided weather protection, safety, luggage room, easy maintenance, comfort, and speed.

The use of computer technology greatly enhanced the design capabilities of manufacturers and designers. Designers are able to simulate various forces working on the bicycle, such as pedaling and road shock. Computer-generated programs make testing simpler, and variations of designs are modified more easily and quickly.

Where To Learn More

Books

Ballantine, Richard and Richard Grant. Richards' Ultimate Bicycle Book. Dorling Kindersley, 1992.

The Bicycle Builder's Bible. TAB Books Inc., 1980.

Bicycle Magazine's Complete Guide to Bicycle Maintenance and Repair, revised ed. Rodale Press, 1990.

Watson, Roderick and Martin Gray. The Penguin Book of the Bicycle, Allen Lane Pub., 1978.

Periodicals

Brown, Stuart F. "The Anybody Bike." Popular Science, August 1991, pp. 58-59, 89.

Schwartz, David M. "Over Hill, Over Dale, On a Bicycle Built for…Goo." Smithsonian, June 1994, pp. 74-86.

Soviero, Marcelle M. "Easy Riders." Popular Science, May 1993, pp. 84-87.

—Audra Avizienis

Bicycling

Sources

Cycling Crazes. In the late nineteenth century, especially in the 1890s, middle-class Americans embraced the bicycle as an instrument of transportation, recreation, and sport. After the Civil War the “boneshaker,” a clumsy and uncomfortable machine upon which the rider sat and propelled himself by walking, was introduced to the nation. Since it interfered with pedestrian traffic, the boneshaker was soon banned from most city streets and parks. The second cycling craze followed the introduction of the “ordinary,” a British cycle, at the 1876 Centennial Exposition in Philadelphia. The ordinary was an odd-looking contraption with a huge front wheel, with a diameter measuring up to sixty inches, and small rear wheel. The ordinary was uncomfortable, dangerous to ride, and expensive to own, costing up to $100. Riders of the ordinary were usually daring middle-class and upper-middle-class young men who had mastered the difficult techniques of mounting, riding, and braking the vehicle.

Organization of Cycling Clubs. The ordinary promoted the development of the nation’s first cycling clubs, the most prominent of which were the Boston Bicycle Club, organized in 1878, and the Chicago Cycling Club, organized in 1879. The Boston club, the first in the United States, grew from ten to one hundred members in four years. These clubs aimed to enhance the pleasurable and competitive aspects of bicycling by holding club meets, tours, and races. The clubs also acted as a pressure group to promote the sport and the rights of cyclists to share public roadways. In 1880 the League of American Wheelmen was formed, with local branches scattered throughout the nation. More so than the Boston or Chicago clubs, the League of American Wheelmen promoted competitive races and fought for improved roads and equal access with horses on public thoroughfares. Its Bulletin, one of eighty-five cycling journals in America, had a readership of nearly one hundred thousand by the turn of the century. In 1883 the League of American Wheelmen achieved an important victory when New York City opened Central Park and Riverside Drive for part of the day to cyclists. Within the next few years few city streets and parkways were off-limits to wheelmen.

The Standard Revolution. A new bicycle, the “standard,” was responsible for the bicycle craze of the 1890s. The standard had equally sized pneumatic tires in front and back, a chain rear drive, a diamond-shaped frame, and more efficient coaster brakes. In addition, the standard was more affordable, with a cheap model costing about $50 and a better one close to $100. Purchasing a bicycle, even one of the expensive models, was easier with installment purchasing plans. Sales of secondhand bicycles made the vehicle available to the working classes, but even these purchasing options were out of reach for the unskilled laborer. Bicycling sometimes worsened class resentments, as the residents of poor neighborhoods resented middle-class folk using their streets as riding paths, interfering with street life, and endangering children at play and pedestrians. Angry city residents were known to pelt cyclists with rocks, glass, garbage, eggs, and vegetables, and blocked their paths with pushcarts. In 1896 anarchists and socialists led community opposition to the paving of streets in certain neighborhoods of New York because it would make the community open to speeding cyclists.

Height of the Cycling Craze. By 1895 there were five hundred cycling clubs in America. Each had its own distinctive uniform worn by members on their outings, which could go as far as one hundred miles at a time. Riders represented an important subcommunity of sportsmen, as they constituted significant voting blocs who would support politicians that advocated road and highway improvement and equal access to streets and parks for cyclists. In 1897, when Carter H. Harrison II ran for the first of his five terms as mayor of Chicago, he became an active cyclist and participated in one-hundred-mile tours in order to gain the support of the cycling fraternity. Cycling clubs also sponsored races, and cycling gained popularity as a spectator sport in the 1890s. One of the most popular races was the fifteen-mile race from Chicago to Pullman held each Memorial Day that attracted two hundred to four hundred contestants. Popular from the 1870s to the 1920s were indoor professional track races. The most outstanding racing cyclist of the era was Marshall “Major” Taylor, an African American, who captured the national sprint championships in 1898, 1899, and 1900 and broke many national and world records before retiring in 1910. In 1897 white racers tried to bar him from the tracks, but race promoters and bicycling manufacturers supported Taylor’s entry into the events. The success of the cycling craze was due to the masses, as there numbered more than one million cyclists in 1893, a figure that more than quadrupled by 1896.

Bicycling and Health Reform. Bicycling received strong support from physicians and other health promoters as exercise for sedentary urban workers and women. Influenced by the cult of masculinity and the notion of the strenuous life, middle-class urbanits embraced the healthful benefits of cycling. Riding a bicycle provided exercise and fresh air and could be enjoyed alone or with friends. Bicycling was one of the few sports socially sanctioned for participation by women, who had traditionally viewed sports as physically taxing and unfeminine. Bicycling, moreover, promoted fashion changes in women’s garments, as women cyclists opted for less restrictive clothes, reflecting the broader social freedom and independence provided them by the machine. Although most physicians encouraged people to use the bicycle for exercise, others were more cautious, warning that overexertion on the bicycle could lead to heart strain and breathlessness. These physicians also cautioned women of childbearing age from excessive cycling, believing that the seat might injure the reproductive organs.

Decline. By the turn of the century there were ten million bicycles in the United States, but the bicycle fad had passed. The market was saturated, and innovative manufacturers were turning to a more sophisticated vehicle, the automobile. While in other parts of the world the bicycle was still regarded as a means of transportation, Americans began to see it as a child’s toy. The automobile replaced the bicycle in the hearts of Americans because it was more exciting and ownership conferred greater prestige. Also, the automobile rendered roadways less safe for cyclists. At its height, however, the bicycle epitomized the progress of civilization, symbolizing the victory of technology over the environment.

Sources

Norman L. Dunham, “The Bicycle Era in American History,” dissertation, Harvard University, 1956;

Richard Harmond, “Progress and Flight: An Interpretation of the American Cycle Craze of the 1890s,” Journal of Social History, 5 (Winter 1971): 238-250;

Robert A. Smith, A Social History of the Bicycle: Its Early Life and Times in America (New York: American Heritage Publishing, 1972).

Bicycling

Although most Americans in the twentieth century associate bicycles and bicycling with children, Europeans, or fitness buffs, a bicycle craze among adults swept the United States in the late 1880s and 1890s that stimulated much excitement and new ways of thinking about transportation. Capitalists created a thriving and valuable bicycle manufacturing industry and a well-developed trade press, as leaders of substantial influence emerged and the industry made rapid advances in design and technology. Major pioneers in aviation (the Wright brothers) and the automobile industry (Henry Ford) got their start as bicycle designers and mechanics, applying their expertise to new motorized forms of transportation.

The early industry gained its footing in the late 1870s when Colonel Albert Pope, a successful Boston industrialist, converted an old sewing machine factory into a bicycle plant. Pope set about building an empire, hiring skilled machinists and die makers to craft interchangeable parts, enabling him to make his high-wheel bicycles for a mass market. Pope also founded the leading bicycle publication, Outing, in 1882. The industry became embroiled in a series of bitter legal battles over patent rights in the mid-1880s, but in 1886 everything changed with a major innovation in bicycle design from Europe: the "safety" bicycle. The new style introduced chain-driven gearing, allowing inventors to replace the dangerous high-wheel design with two equally sized wheels and the now-standard diamond frame. These changes significantly increased the safety of bicycles without sacrificing speed, thus creating a much larger market for bicycles. After 1886 prices fell, democratizing what had once been an elite sport. Bicycle clubs sprouted, and the nation developed bicycle fever. Sales soared as comfort and speed improved, reaching a peak in 1897 when about three thousand American manufacturers sold an estimated two million bicycles.

The popularity of bicycles in the 1890s engendered heated debates over the decency of the fashionable machines. Advocates catalogued their benefits: economic growth, the freedom of the open road, a push for improved roads, increased contact with the outdoors, and the leveling influence of providing cheap transportation for the workingman. Critics, however, attacked bicycles as dangerous (be-cause they upset horses), detrimental to the nervous system (because riding required concentration), and antithetical to religion (because so many people rode on Sundays). In addition, many critics questioned the propriety of women riding bicycles. Particularly scandalous to the skeptics was the tendency of women cyclists to discard their corsets and don bloomers in place of long skirts, but censors also reprimanded courting couples for using bicycles to get away from parental supervision and criticized women's rights advocates for emphasizing the emancipatory qualities of their machines.

By the turn of the century the bicycle craze abated and, despite an urban indoor track racing subculture that persisted until World War II using European imports, bicycles survived for a number of decadesprimarily as children's toys. The quality of bicycles, which found their major retail outlets between 1900 and 1930 in department stores, deteriorated substantially. Then, in 1931, the Schwinn bicycle company sparked a minor revolution in the industry by introducing the balloon tire, an innovation from motorcycle technology that replaced one-piece inflatable tires with an outside tire coupled with a separate inner tube. The strength and comfort of these new tires could accommodate much heavier, sturdier frames, which could better withstand the use (and abuse) of children riders. Taking a cue from the 1933 Century of Progress Exposition in Chicago, a showcase for Art Deco styling, Schwinn inspired more than a decade of streamlined bicycles—and innumerable suburban childhood dreams of freedom and exhilaration—with its 1934 Aerocycle. Bicycle design changed again slightly in the mid-1940s when manufacturers began to capitalize on the baby boom market. Following the practice of the automobile industry, bicycle designers created their own version of planned obsolescence by styling bicycles differently to appeal to different age groups.

Beginning in the mid-1950s and early 1960s, bicycles again became popular among adults, this time as a healthy form of exercise and recreation. A turning point came in September of 1955, when President Dwight Eisenhower suffered a heart attack. His personal physician, Dr. Paul Dudley White, happened to be an avid cyclist who believed that bicycling provided significant cardiovascular benefits. When he prescribed an exercise regimen featuring a stationary bicycle for the president, the ensuing publicity generated a real, if small, increase in bicycling among adults. Small local racing clubs in California kept the idea of cycling as adult recreation alive through the 1950s, but not until the exercise chic of the 1960s spread from the West Coast to other parts of the country did adult bicycles become a significant proportion of all sales. Bicycle manufacturers responded by introducing European-style ten-speed gearing, focusing on racing, touring, and fitness in their marketing. The popularity of bicycling made modest gains through the 1970s and 1980s as racing and touring clubs gained membership and local bicycle competitions became more common around the country, including races called triathlons that mixed running, bicycling, and swimming.

Beginning in the early 1980s, a new breed of bicycles called "mountain bikes"—sturdy bicycles designed with fat, knobby tires and greater ground clearance for off-road riding—overtook the adult market with astonishing rapidity. The new breed of bicycles first reached a mass market in 1981, and by 1993 sales approached 8.5 million bicycles, capturing the large majority of the United States market. Earning substantial profits from booming sales, designers made rapid improvements in frame design and components that made new bicycles appreciably lighter and more reliable than older designs. Off-road races grew in number to rival the popularity of road racing, and professional races gained corporate sponsorship through the 1980s and 1990s. Somewhat ironically, however, only a small percentage of mountain bike owners take their bicycles off-road. Buyers seem to prefer their more comfortable, upright style compared to road racing machines, but use them almost exclusively on paved roads for exercise and eco-friendly short-distance transportation.

—Christopher W. Wells

Further Reading:

Pridmore, Jay, and Jim Hurd. The American Bicycle. Osceola, Wisconsin, Motorbooks International Publishers, 1995.

Smith, Robert A. A Social History of the Bicycle: Its Early Life and Times in America. New York, American Heritage Press, 1972.