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A bicycle is a two wheeled vehicle driven by the riders feet pushing on cranks or pedals. A common misconception is that the earliest form of bicycle was the dandy-horse, which was pushed along by the rider's feet. However, while both the dandy-horse and the later bicycle are both velocipedes, the dandy-horse is not propelled by cranks.
The first bicycle was introduced to England from France in 1868, and comprised two solid wheels of equal size fitted to a frame, much like a modern bicycle in appearance, with a saddle fitted in the centre and propelled by cranks attached to the front wheel. This vehicle provided such a bumpy ride to the rider that it became popularly known as 'the bone-shaker'. Later came the Penny-Farthing with pedals fixed to the large front wheel which was made large to achieve high speeds. Later still, around 1895, came the safety bicycle with pedals driving the rear wheel by way of a chain, and the rider sitting upon a saddle set back from the front wheel so as to reduce the chances of falling forwards over the handlebars, from this developed the Raleigh bicycle design of 1900 which forms the basis of the modern bicycle. In 1888 the two-person tandem bicycle was invented.
In 1906 it was reported that speeds of 50 mph were attained on a bicycle. Around the same time, slightly earlier, the motorised bicycle (motorcycle or motorbike) was invented.
A typical bicycle is comprised of several parts. The principal and essential being: the frame, front forks, wheels, pedals, saddle, handlebars, chain and brakes. The largest part of the bicycle is the frame, and these vary in design depending upon the specialised intention of the bicycle.
A frame for a BMX bicycle being small, heavily braced and made of aluminium. The frame for BMX xyxling needs to be strong so as to endure the stresses of the bumpy ride, and the saddle low as competitors never sit down during a competition and as such they need space to sprint and jump with ease.
Cross-Country cycle frames are generally made of aluminium and carbon-fibre so as to be light weight. They are relatively small frames to allow quick and easy mounting and dismounting off road, and strong to endure off-road bumpy conditions. The smaller frames are often compensated for by having a longer seat post to allow a normal height saddle position.
The cycle speedway bicycle frame is designed primarily for strength, and as such is typically made from steel or aluminium.
Road racing bicycle frames are designed to be light and stiff. Traditionally they ewre made of steel, but by the start of the 21st century carbon fibre was being used for the more expensive models as this offered the same stiffness at reduced weight. The design of the tubes also developed over time, tubes becoming of a larger diameter, but thinner walls, to allow the same stiffness with reduced weight.
Bicycles are fitted with various types of brake, the most popular being the calliper, cantilever, hydraulic or disc and the V brake. The most common form of brake found on leisure bicycles, is that form used also on road racing bicycles. The calliper brake. Calliper brakes are a very efficient means of rim braking and basically comprise two blocks of rubber or plastic which are squeezed onto the wheel rim when the brake lever is squeezed by the ride.
Cantilever brakes operate on the same principal as calliper brakes, but are of a slightly different design at the wheel end, offering increased clearance between the tyre and the brake pads and as such are frequently employed for cyclo-cross bicycles and mountain bikes.
The most efficient form of rim brake is the V brake. The V brake also offers the most clearance of any rim braking system, and is most often found on mountain bikes.
Hydraulic or disc brakes are the most efficient and powerful form of bicycle brake. They use the wheel hub to brake, rather than the rim. Disc brakes offer the most clearance, and as such are used on mountain bikes, but are also expensive to fit and maintain.
Bicycle wheels are generally of one of three types. The most common and traitional bicycle wheel is the spoked wheel, comprising a rim connected to the central bub by a series of thin metal rods known as spokes. Spoked wheels are light in weight. Less common than spoked wheels, but offering greater strength and durability at the expense of weight are mag wheels which comprise a rim attached to the hub by a few, thick solid plastic bars. Solid wheels, also known as disc wheels, are made from composite material or carbon fibre are very strong, stiff, aerodynamic and very expensive. They are rarely used except as rear wheels in time-trialing and track racing.
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Cycle is a term used for every uniformly-returning succession of the same events. On such successions or cycles of years rests all chronology, particularly the calendar. Our common solar year, determined by the periodical return of the sun to the same point in the ecliptic, everybody knows contains fifty-two weeks and one day, and leap-year a day more. Consequently in different years the same day of the year cannot fall upon the same day of the week. And as every fourth year is a leap-year, it will take twenty-eight years (4x7) before the days return to their former order according to the Julian calendar. Such a period is called a solar cycle. The cycle of the moon, or golden number, or Metonic cycle, is a period of nineteen years after which the new and full moons return on the same days of the month.
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The dandy-horse was an early velocipede or cycle. It resembled a bicycle, but hadn't any pedals and so the rider propelled it by pushing it along with his feet on the ground.
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An epoch, or era, is a fixed point of time, commonly selected on account of some remarkable event by which it has been distinguished, and which is made the beginning or determining point of a particular year from which all other years, whether preceding or ensuing, are computed. In the Christian countries, the creation and the birth of Christ are the most important of the historical epochs. The creation has formed the foundation of various chronologies, the chief of which are: 1. The epoch adopted by Bossuet, Ussher, and other Catholic and Protestant divines, which places the creation in 4004 BC. 2. The Era of Constantinople (adopted by Russia), which places it in 5508 BC. 3. The Era of Antioch, used until 284 AD, placed the creation 5502 BC. 4. The Era of Aexandria, which made the creation 5492 BC. This is also the Abyssinian Era. 5. The Jewish Era, which places the creation in 3760 BC.
The Greeks computed their time by periods of four years, called Olympiads, from the occurrence every fourth year of the Olympic games. The first Olympiad, being the year in which Coroebus was victor in the Olympic games, was in the year 776 BC.
The Romans dated from the supposed era of the foundation of their city (Ab Urbe Condita, A.U.C.), the 21st of April, in the third year of the sixth Olympiad, or 753 BC (according to some authorities 752 BC).
The Christian Era, or mode of computing from the birth of Christ as a starting-point, was first introduced in the 6th century, and was generally adopted by the year 1000. This event is believed to have taken place earlier, perhaps by four years, than the received date.
The Julian epoch, based on the coincidence of the solar, lunar, and indictional periods, is fixed at 4713 BC, and is the only epoch established on an astronomical basis.
The Mohammedan Era, or Hejira, commences on the 16th of July, 622, and the years are computed by lunar months.
The Chinese traditionally reckoned their time by cycles of 60 years. Instead of numbering them as we do, they traditionally gave a different name to every year in the cycle.
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Eschatology is a term used primarily in Christian and Jewish theology to refer to the 'last things', including the ultimate fate of the world and the individual soul. However, almost all religions of the world have eschatological features, which may be divided into those based on mythological explanations of the origins and end of the world and those based on historical explanations. The biblical accounts of the history of the Jewish people and the teaching and parables of Jesus are examples of historical eschatology, leading to millenarian expectations of the coming of the Messiah among Jews, and of the Second Coming among Christians. Contrasting with such views is the expectation of the apocalyptic or cataclysmic intervention of God in history. In both Hinduism and Buddhism, eschatological beliefs focus on the longing for release from the cycle of birth and rebirth.
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In chronology, the golden number is a number showing the year of the moon's cycle; so called from having formerly been written in the calendar in gold. To find the golden number add 1 to the given year, and divide the sum by 19, what remains will be the number required, unless 0 remain, in which case 19 is the golden number.
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The Hitachi Zaxis is a range of Japanese medium hydraulic excavators. The Zaxis range are powered by an Isuzu AH-6HK1X 4-cycle water-cooled, direct injection turbocharged, Intercooled 6-cylinder engine providing a top speed of 5 kmh. The Zaxis range are fitted with caterpillar tracks and can traverse a 35 degree incline safely. Various attachments can be fitted to the boom arm for use in digging and demolition.
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Indiction is a chronological term for a cycle of fifteen years. It was originally a Roman term, possibly connected with the periodical publication of taxation tariffs. It was first employed in 312. The position of any year in an indiction is found by adding three to the dominical number, and dividing the result by fifteen. The remainder gives the position.
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In astronomy, nutation is a slight 'nodding' of the Earth in space, caused by the varying gravitational pulls of the Sun and Moon. Nutation changes the angle of the Earth's axial tilt by about nine seconds of arc to either side of its mean position, a complete cycle taking just over 18.5 years.
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Sunbeam were a British manufacturer of bicycles and later motor cycles, founded by John Masrston in Wolverhampton around 1871, experiments into motor cycles beginning in about 1903 and then being halted following a fatal accident in 1904 until in 1911 an engineer was brought in and production of the Sunbeam motor cycle range began in 1912 and ceased in the late 1930's with the demise of the Sunbeam company.
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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