Bicycle

A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a vehicle that a person powers by pedaling. Sometimes a small motor helps. It has two wheels, one behind the other, attached to a frame. A person who rides a bicycle is called a cyclist or bicyclist.

The bicycle was invented in Europe in the 19th century. By the early 21st century, there were more than 1 billion bicycles in the world. In many places, bicycles are a main means of transport. People also enjoy them for recreation, and they have been turned into children's toys. People use bicycles for commuting, shopping, fitness, military and police work, courier services, bicycle racing, and artistic cycling.

The basic shape of a typical upright or "safety" bicycle has changed very little since the first chain-driven model was made around 1885. Many details have been improved, especially with the arrival of modern materials and computer-aided design. These changes have led to many special designs for different kinds of cycling. In the 21st century, electric bicycles have become popular.

The bicycle has had a big effect on society, both in culture and in helping to advance modern industrial methods. Several parts that later played a key role in the development of the car were first invented for the bicycle. These include ball bearings, pneumatic tires, chain-driven sprockets, and tension-spoked wheels.

Etymology

The first known use of the word bicycle in English print was in The Daily News in 1868. It described "Bysicles and trysicles" on the Champs Elysées and Bois de Boulogne. In 1828, the word was first used in French for a two-wheeled chaise, which was a carriage pulled by a horse. The bicycle was a improvement on the velocipede, though for a time people used the two words in similar ways.

Other words for the bicycle include "bike", "pushbike", "pedal cycle", or "cycle". In Unicode, the code point for "bicycle" is U+1F6B2. In HTML, the entity 🚲 shows 🚲.

History

Main article: Cycling

Bicycles help people get around, such as bicycle commuting to work or school and utility cycling for everyday trips. Riding a bike uses about 80 percent less energy than walking the same distance. Mail carriers, paramedics, police, messengers, and people for deliveries also use bicycles for their jobs. In the military, bicycles were used for communications, reconnaissance, moving troops, carrying supplies, and patrolling, such as in bicycle infantries.

People also ride bicycles for fun. This includes bicycle touring, mountain biking, physical fitness, and play. Bicycle sports include racing, BMX racing, track racing, criterium, roller racing, sportives, and time trials. Bicycles are also used for entertainment, such as in organised mass rides, artistic cycling, and freestyle BMX.

Technical aspects

Bicycles have been improved again and again over time. Modern materials and computer design have made bicycles safer and more comfortable. They have also helped create many more types of bicycles.

Types

Main article: List of bicycle types

Bicycles can be grouped in many ways. They can be grouped by their use, number of riders, build, gears, or how they are powered. Common types include utility bicycles, mountain bicycles, racing bicycles, touring bicycles, hybrid bicycles, cruiser bicycles, BMX bikes and electric bicycles. Less common types include tandems, low riders, tall bikes, fixed gear, folding models, amphibious bicycles, cargo bikes and recumbents.

Unicycles, tricycles and quadracycles are not strictly bicycles, because they have one, three, or four wheels. They are still called cycles. Some other languages do not use the word "bi," such as "velo" or "fiets."

Dynamics

A bicycle stays upright while moving forward when it is steered to keep its center of mass over the wheels. The rider usually does this steering. In some conditions, the bicycle may steer itself.

To turn, the rider and bicycle must lean into the turn. This lean is caused by a method called countersteering. The rider can do this by turning the handlebars or by leaning the bicycle. When braking, a short or tall bicycle can flip forward. A rider can use this force on purpose to lift the back wheel and balance on the front. This trick is known as a stoppie, endo, or front wheelie.

Performance

The bicycle is very efficient, both for the body and mechanically. When traveling slowly, or with an aerodynamic cover called a fairing, it is the most efficient human-powered way to travel a set distance. Up to 99% of the energy a rider puts into the pedals reaches the wheels. Gears may reduce this by 10–15%, and a small amount is lost to tire slip.

At low to medium speeds of about 16–24 km/h (10–15 mph), a rider uses only the power needed to walk. Air drag increases quickly as speed rises, so much more power is needed to go faster. When a rider sits upright, the rider's body creates about 75% of the total drag. The fastest recorded speed on a flat surface from a standing start was over 92 km/h (57 mph). It was set in the hour record in 2016, on a highly streamlined bicycle.

Parts

A bicycle can have up to a thousand parts.

Most modern bicycles have an upright truss frame, often a diamond frame. It is made of two triangles: a front triangle and a rear triangle. The headset sits in the head tube. It holds the fork so the front wheel can turn smoothly for steering and balance. The bottom bracket sits at the bottom of the frame. The rear wheel's axle is held at the dropouts. Older women's frames had a lower standover height. This design is called a step-through frame or open frame. It let riders get on and off while wearing a skirt or dress. A mixte is a version of this style. A recumbent bicycle is one where the rider leans back. It is more aerodynamic than an upright bike. The world's fastest bicycle is a recumbent. However, this type was banned from competition in 1934 by the Union Cycliste Internationale. Frames have been made from different materials over time. They have used steel, aluminum joined by welding, and titanium. Today many use carbon fibre, which is very light. Wood and bamboo have been used since 1894. Bamboo is a natural composite material with good stiffness.

The drivetrain starts with the pedals. The pedals turn the cranks. Most bicycles use a chain to send power to the rear wheel. A variable gear ratio helps a rider keep a comfortable cadence on different ground. Some bikes use hub gears. Most use a derailleur system instead. It moves the chain between a chainring and cassette or freewheel sprockets. Low gears make pedalling easier uphill. High gears help on flat roads and downhill. Different gears and ranges of gears suit different riders and styles of cycling.

The handlebars connect to a stem. The stem connects to the fork that holds the front wheel. The whole part turns around the steering axis. The headset bearings hold it in place. Upright handlebars curve back towards the rider. Drop handlebars curve forward and down. They let riders lean into a more aerodynamic position. Mountain bikes often have straight or riser bars.

Saddles vary by rider. Cushioned saddles suit short trips. Narrower saddles leave more room for leg movement. A recumbent bicycle has a reclined chair-like seat. Some riders find this more comfortable. It may have steering under or over the seat.

Brakes may be rim brakes, hub brakes, or disc brakes. Most road bikes use rim brakes. Disc brakes are more common on mountain bikes, tandems, and recumbents. Hand-operated brakes send force through cables or hydraulic lines to slow the bike. Some track bicycles have no brakes. They are fixed-gear, so riders slow down by pushing against the pedals.

Suspension keeps the wheels in contact with the ground. It also helps isolate the rider from rough surfaces. It is mainly found on mountain bikes and is important on recumbents. Road bicycles usually have no suspension.

Tires vary by purpose. Road bicycles typically use narrow tires. Some are smooth slick tires. They are inflated to high pressure. Off-road tires are wider. They have treads for mud or metal studs for ice.

Many utility bicycles include extras. These can include fenders, chainguards, kick stands, bike locks, baskets, luggage carriers, and panniers. Parents may add child seats or a trailer. Other accessories include toe-clips, clipless pedals, cyclocomputers, lights, cages, and bells. Children's bikes may have bike horns, streamers, and spoke beads. Training wheels help beginners. A balance bike teaches riding more effectively. Bicycle helmets can reduce injury. They are required by law in many places. Bike trainers let riders cycle while the bike stays still.

Several standards help make spare parts interchangeable and keep products safe. The International Organization for Standardization (ISO) has a technical committee for cycles. The European Committee for Standardization (CEN) has its own committee. Its cycle standards are meant to match ISO standards.

Industry

Manufacturing and sales

Maintenance and repair

A bicycle can last for decades if it is cared for. Like other machines with moving parts, it needs regular maintenance, and worn parts must be replaced. A bicycle is simpler than a car, so some cyclists do at least some of the work themselves. Bicycle mechanics at local bike shops can do full services. There are also hundreds of community bicycle groups around the world, where volunteers teach people how to fix their own bikes. Some cyclists buy roadside help from the Better World Club or the American Automobile Association, where it is offered. Tires need the right amount of air and wear out over time. A puncture often shows that a tire is worn. Very few bicycle parts can be repaired, so a broken part is usually replaced. The most common problem on the road is a puncture in the inner tube. The tube can be patched or replaced. Some tires are more puncture-resistant than others. Many use Kevlar, but they can be heavier and harder to fit.

Special tools are used in shops and on the road. Many cyclists carry a tool kit. It may include a hand pump or CO₂ pump, tire levers, spare tubes, patches, French chalk, wrenches, hex keys, screwdrivers, and a chain tool. Some multi-tools made for cycling combine many of these into one small device. Some specialized parts need complex tools, including some made only by the manufacturer.

Social and historical aspects

See also: Cycling infrastructure and History of cycling infrastructure

See also: Bicycling and feminism

See also: Cycling § Environmental_impact, and Electric_bicycle § Environmental_effects

The bicycle has had a big effect on people and society, both in culture and in industry. Around 1900, bicycles helped ease crowding in cities, because workers could live in roomier homes in the suburbs and ride to work. They also reduced the need for horses and let people travel into the countryside for fun. A bicycle uses much less energy than walking, and it is three to four times as fast. Today, urban planning in many cities includes cycling paths, such as bikeways, to reduce traffic congestion and air pollution. Many cities run bicycle sharing systems. The first was the White Bicycle plan in Amsterdam in 1965, followed by yellow bicycles in La Rochelle. In the Netherlands, train stations offer free bicycle parking. In Trondheim, Norway, the Trampe bicycle lift helps cyclists climb a steep hill. Some towns, such as Ílhavo in Portugal, have had bicycle culture for generations. People who use a mixed-mode commute ride a bike to and from train stations, and folding bicycles are useful for this. Some tech sector companies chose office locations where biking would be easy. For example, Foursquare was a company whose CEO, Dennis Crowley, pedaled to meetings. At that time, venture capitalists were funding the company. Bicycles are also celebrated in the arts, such as at the Bicycle Film Festival.

The safety bicycle gave women new freedom, which helped their emancipation in Western nations. The bicycle came to symbolize the New Woman of the late 19th century. A bicycle craze in the 1890s led to rational dress, which freed women from corsets and long skirts. Suffragists saw the bicycle as a "freedom machine" for women. Susan B. Anthony praised it in the New York World. Frances Willard, president of the Woman's Christian Temperance Union, wrote about the joy of riding. In 1985, Georgena Terry started the first women-specific bicycle company. Bicycle making also helped other industries. Bicycle manufacturing led to better metalworking for parts such as ball bearings and washers, which later helped build early cars and aircraft. Wilbur and Orville Wright ran the Wright Cycle Company during the bike boom of the 1890s. Bicycle makers also used methods like mass production, which were later copied by Ford and General Motors. The Rover Company, Morris Motors in Oxford, and Škoda all began in the bicycle business. Today, over 60% of the world's bicycles are made in China. In 2011, bicycle sales in Italy were higher than new car sales.

Bicycle emissions come from their production and from the food used for pedalling, or from the electricity used by electric bikes. Their materials are mainly steel, aluminium, and carbon fibre, and the metals can be recycled. Another source of emissions is rubber pollution from tire wear. Early on, bicycles faced restrictions, just as automobiles did. Albert A. Pope took legal action for cyclists. The Vienna Convention on Road Traffic of the United Nations considers a bicycle a vehicle. Many jurisdictions make it an offense to ride a bicycle that is not safe to use on the road. Bicycles are popular targets for bicycle theft, because they are valuable and easy to resell. Most have serial numbers that can help prove who owns them.