Bicycle

I

Introduction

Bicycle, vehicle consisting of two wheels fixed in tandem to a frame, steered by handlebars, and propelled by an arrangement of pedals and gears driven by the feet. The name of the modern vehicle dates from 1869. Various precursors of this machine were known as velocipedes, from a French name dating from the late 18th century. From the 1960s onward, air pollution from car exhaust has caused increasing concern, and the popularity of cycling, both to and from work and for recreation, has increased tremendously. In many cities cycle lanes and special cycle paths were set up. The growing emphasis on physical fitness in the 1980s and 1990s added to this popularity. In countries such as the Netherlands and Denmark, bicycles are an important means of travel, and most roads have separate bicycle lanes. In China the bicycle is the most widely used vehicle.

II

History

Crude two-wheeled vehicles propelled by the feet were popular as early as the second half of the 17th century. In 1690 a Frenchman invented the célérifère, consisting of a wooden beam to which the wheels were affixed. The vehicle had no handlebar; the rider sat on a cushion on the beam and propelled and steered the machine by pushing the feet against the ground. In 1816 a German nobleman, Baron von Drais, designed the first two-wheeled vehicle with a steering device. This machine, named the draisine (or, alternatively, the draisienne) after its inventor, had a handlebar that pivoted on the frame, enabling the front wheel to be turned. Improvements were later developed by French, German, and British inventors.

In England these early models were known as hobby horses; the name “dandy horse” was applied particularly to the expensive pedestrian curricle, invented in 1818. The curricle was lighter in weight than the draisine and had an adjustable saddle and elbow rest. It was patented in the United States in 1819 but aroused little interest.

In 1839 driving levers and pedals were added to a machine of the draisine type by a Scot, Kirkpatrick Macmillan. These innovations enabled the rider to propel the machine with the feet off the ground. The driving mechanism consisted of short cranks fixed to the rear wheel hub and connected by rods to long levers, which were hinged to the frame close to the head of the machine. The connecting rods were joined to the levers at about one third of their length from the pedals. The machine was propelled by a downward and forward thrust of the foot. In 1846 an improved model of this machine, designed by a Scotsman, acquired the name “dalzell” and was widely used in England.

The direct precursor of the modern bicycle was the French crank-driven, loose-pedalled velocipede, which became popular in France about 1855. The frame and wheels were made of wood. The tyres were of iron, and the pedals were attached to the hub of the front, or driver, wheel, which was slightly higher than the rear wheel. In England this machine was known as the boneshaker, because of its effect on a rider pedalling over a rough road or a cobblestone street. In 1869 in England, solid rubber tyres mounted on steel rims were introduced in a new machine, which was the first to be patented under the modern name “bicycle”. In 1873 James Starley, an English inventor, produced the first machine incorporating most of the features of the so-called ordinary, or high-wheel, bicycle. The front wheel of Starley’s machine was as much as three times as wide as the rear wheel.

The modifications and improvements of the next 15 years included the ball-bearing and the pneumatic tyre. These inventions, along with the use of weldless steel tubing and spring seats, brought the ordinary bicycle to its highest point of development. The excessive vibration and instability of the high-wheel bicycle, however, caused inventors to turn their attention to reducing the height of the bicycle. About 1880 the so-called safety, or low, machine was developed. The wheels were of nearly equal size, and the pedals, attached to a sprocket through gears and a chain, drove the rear wheel.

III

Bicycles Today

Nowadays, bicycles are made in different frame sizes to suit cyclists of different heights, and are based on a range of styles, including lightweight (for racing and touring events); middleweight (for shorter rides); juvenile (such as the BMX); and speciality (such as tandem bikes, or tricycles for young children).

Modern, multi-speed bicycles have multiple gears. Low gears are for pedalling uphill and high gears, for high speeds or cycling downhill. The lightweight ten-speed racing cycle, with cable-and-calliper handbrakes and narrow, high-pressure tyres, became popular in the 1980s. Later, the all-terrain bike, with deep-tread tyres and a heavier frame, was rugged, safe, and manoeuvrable.

Relative to distance travelled, cyclists face a greater risk of death or injury on the roads. In most countries bicycles have to meet road safety requirements, particularly the inclusion of front, rear, and wheel reflectors, and cyclists are usually encouraged to wear protective helmets and comply with traffic laws, such as stopping at traffic lights and observing pedestrians’ right of way.