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A wheel is a circular component that is intended to rotate on an axle bearing. The wheel is one of the key components of the
wheel and axle The wheel and axle is a simple machine consisting of a wheel attached to a smaller axle so that these two parts rotate together in which a force is transferred from one to the other. The wheel and axle can be viewed as a version of the lever, wi ...
which is one of the six simple machines. Wheels, in conjunction with axles, allow heavy objects to be moved easily facilitating movement or transportation while supporting a load, or performing labor in machines. Wheels are also used for other purposes, such as a
ship's wheel A ship's wheel or boat's wheel is a device used aboard a water vessel to steer that vessel and control its course. Together with the rest of the steering mechanism, it forms part of the helm. It is connected to a mechanical, electric servo, or ...
, steering wheel,
potter's wheel In pottery, a potter's wheel is a machine used in the shaping (known as throwing) of clay into round ceramic ware. The wheel may also be used during the process of trimming excess clay from leather-hard dried ware that is stiff but malleable, a ...
, and
flywheel A flywheel is a mechanical device which uses the conservation of angular momentum to store rotational energy; a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, as ...
. Common examples are found in
transport Transport (in British English), or transportation (in American English), is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land ( rail and road), water, cable, pipelin ...
applications. A wheel reduces
friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of ...
by facilitating motion by
rolling Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact ...
together with the use of
axles An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearin ...
. In order for wheels to rotate, a moment needs to be applied to the wheel about its axis, either by way of gravity or by the application of another external force or
torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
. Using the wheel,
Sumerians Sumer () is the earliest known civilization in the historical region of southern Mesopotamia (south-central Iraq), emerging during the Chalcolithic and early Bronze Ages between the sixth and fifth millennium BC. It is one of the cradles of c ...
invented a device that spins clay as a potter shapes it into the desired object.


Terminology

The English word '' wheel'' comes from the
Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlers in the mid-5th c ...
word , from
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic bran ...
, from
Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. Its proposed features have been derived by linguistic reconstruction from documented Indo-European languages. No direct record of Proto-Indo- ...
, an extended form of the root "to revolve, move around". Cognates within Indo-European include Icelandic "wheel, tyre",
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
, and
Sanskrit Sanskrit (; attributively , ; nominally , , ) is a classical language belonging to the Indo-Aryan branch of the Indo-European languages. It arose in South Asia after its predecessor languages had diffused there from the northwest in the late ...
, the last two both meaning "circle" or "wheel".


History

The place and time of the invention of the wheel remains unclear, because the oldest hints do not guarantee the existence of real wheeled transport, or are dated with too much scatter.
Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...
n civilization is credited with the invention of the wheel. However, unlike other breakthrough inventions, the wheel cannot be attributed to a single nor several inventors. Evidence of early usage of wheeled carts has been found across the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
, in
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
,
Eastern Europe Eastern Europe is a subregion of the European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russia, whic ...
,
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
and China. It is not known whether Chinese, Indians and Europeans invented the wheel independently or not. The invention of the solid wooden disk wheel falls into the late
Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several p ...
, and may be seen in conjunction with other technological advances that gave rise to the early
Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...
. This implies the passage of several wheelless millennia even after the invention of agriculture and of
pottery Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and ...
, during the
Aceramic Neolithic Pre-Pottery Neolithic A (PPNA) denotes the first stage of the Pre-Pottery Neolithic, in early Levantine and Anatolian Neolithic culture, dating to years ago, that is, 10,000–8,800 BCE. Archaeological remains are located in the Levantine and U ...
. * 4500–3300 BCE ( Copper Age): invention of the
potter's wheel In pottery, a potter's wheel is a machine used in the shaping (known as throwing) of clay into round ceramic ware. The wheel may also be used during the process of trimming excess clay from leather-hard dried ware that is stiff but malleable, a ...
; earliest solid wooden wheels (disks with a hole for the axle); earliest wheeled vehicles;
domestication of the horse A number of hypotheses exist on many of the key issues regarding the domestication of the horse. Although horses appeared in Paleolithic cave art as early as 30,000 BCE, these were wild horses and were probably hunted for meat. How and when ho ...
* 3300–2200 BCE (
Early Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...
) * 2200–1550 BCE ( Middle Bronze Age): invention of the spoked wheel and the chariot The
Halaf Tell Halaf ( ar, تل حلف) is an archaeological site in the Al Hasakah governorate of northeastern Syria, a few kilometers from the city of Ra's al-'Ayn near the Turkish border. The site, which dates to the 6th millennium BCE, was the fir ...
culture of 6500–5100 BCE is sometimes credited with the earliest depiction of a wheeled vehicle, but this is doubtful as there is no evidence of Halafians using either wheeled vehicles or even pottery wheels. Precursors of pottery wheels, known as "tournettes" or "slow wheels", were known in the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...
by the 5th millennium BCE. One of the earliest examples was discovered at Tepe Pardis,
Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
, and dated to 5200–4700 BCE. These were made of stone or clay and secured to the ground with a peg in the center, but required significant effort to turn. True potter's wheels, which are freely-spinning and have a
wheel and axle The wheel and axle is a simple machine consisting of a wheel attached to a smaller axle so that these two parts rotate together in which a force is transferred from one to the other. The wheel and axle can be viewed as a version of the lever, wi ...
mechanism, were developed in
Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...
(
Iraq Iraq,; ku, عێراق, translit=Êraq officially the Republic of Iraq, '; ku, کۆماری عێراق, translit=Komarî Êraq is a country in Western Asia. It is bordered by Turkey to the north, Iran to the east, the Persian Gulf and K ...
) by 4200–4000 BCE. The oldest surviving example, which was found in Ur (modern day
Iraq Iraq,; ku, عێراق, translit=Êraq officially the Republic of Iraq, '; ku, کۆماری عێراق, translit=Komarî Êraq is a country in Western Asia. It is bordered by Turkey to the north, Iran to the east, the Persian Gulf and K ...
), dates to approximately 3100 BCE. Wheels of uncertain dates have also been found in the Indus Valley civilization, a 4th millennium BCE civilization covering areas of present-day India and
Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's fifth-most populous country, with a population of almost 243 million people, and has the world's second-lar ...
. The oldest indirect evidence of wheeled movement was found in the form of miniature clay wheels north of the Black Sea before 4000 BCE. From the middle of the 4th millennium BCE onward, the evidence is condensed throughout
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
in the form of toy cars, depictions, or ruts, with the oldest find in Northern Germany dating back to around 3400 BC. In
Mesopotamia Mesopotamia ''Mesopotamíā''; ar, بِلَاد ٱلرَّافِدَيْن or ; syc, ܐܪܡ ܢܗܪ̈ܝܢ, or , ) is a historical region of Western Asia situated within the Tigris–Euphrates river system, in the northern part of the ...
, depictions of wheeled
wagon A wagon or waggon is a heavy four-wheeled vehicle pulled by draught animals or on occasion by humans, used for transporting goods, commodities, agricultural materials, supplies and sometimes people. Wagons are immediately distinguished from ...
s found on
clay tablet In the Ancient Near East, clay tablets ( Akkadian ) were used as a writing medium, especially for writing in cuneiform, throughout the Bronze Age and well into the Iron Age. Cuneiform characters were imprinted on a wet clay tablet with a sty ...
pictographs A pictogram, also called a pictogramme, pictograph, or simply picto, and in computer usage an icon, is a graphic symbol that conveys its meaning through its pictorial resemblance to a physical object. Pictographs are often used in writing and g ...
at the Eanna district of
Uruk Uruk, also known as Warka or Warkah, was an ancient city of Sumer (and later of Babylonia) situated east of the present bed of the Euphrates River on the dried-up ancient channel of the Euphrates east of modern Samawah, Al-Muthannā, Iraq.Harm ...
, in the Sumerian civilization are dated to c. 3500–3350 BCE. In the second half of the 4th millennium BCE, evidence of wheeled vehicles appeared near-simultaneously in the Northern (
Maykop culture The Maykop culture (, , scientific transliteration: ''Majkop,''), c. 3700 BC– 3000 BC, was a major Bronze Age archaeological culture in the western Caucasus region. It extends along the area from the Taman Peninsula at the Kerch Strait to ...
) and South
Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia (country), Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range ...
and
Eastern Europe Eastern Europe is a subregion of the European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russia, whic ...
( Cucuteni-Trypillian culture). Depictions of a wheeled vehicle appeared between 3631 and 3380 BCE in the Bronocice clay pot excavated in a
Funnelbeaker culture The Funnel(-neck-)beaker culture, in short TRB or TBK (german: Trichter(-rand-)becherkultur, nl, Trechterbekercultuur; da, Tragtbægerkultur; ) was an archaeological culture in north-central Europe. It developed as a technological merger of lo ...
settlement in southern
Poland Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populou ...
. In nearby Olszanica, a 2.2 m wide door was constructed for wagon entry; this barn was 40 m long with three doors, dated to 5000 B.C.E—7000 years old, and belonged to the
neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several p ...
Linear Pottery culture. Surviving evidence of a wheel-axle combination, from Stare Gmajne near Ljubljana in Slovenia (
Ljubljana Marshes Wooden Wheel The Ljubljana Marshes Wheel is a wooden wheel that was found in the Ljubljana Marsh some south of Ljubljana, the capital of Slovenia, in 2002. Radiocarbon dating, performed in the VERA laboratory (Vienna Environmental Research Accelerator) in Vi ...
), is dated within two
standard deviations In statistics, the standard deviation is a measure of the amount of variation or dispersion of a set of values. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while ...
to 3340–3030 BCE, the axle to 3360–3045 BCE. Two types of early Neolithic European wheel and axle are known; a circumalpine type of wagon construction (the wheel and axle rotate together, as in Ljubljana Marshes Wheel), and that of the
Baden culture The Baden culture was a Chalcolithic culture from 3520–2690 BC. It was found in Central and Southeast Europe, and is in particular known from Moravia (Czech Republic), Hungary, southern Poland, Slovakia, northern Croatia and eastern Austria. I ...
in
Hungary Hungary ( hu, Magyarország ) is a landlocked country in Central Europe. Spanning of the Pannonian Basin, Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the ...
(axle does not rotate). They both are dated to c. 3200–3000 BCE. Some historians believe that there was a diffusion of the wheeled vehicle from the Near East to Europe around the mid-4th millennium BCE. Early wheels were simple wooden disks with a hole for the axle. Some of the earliest wheels were made from horizontal slices of tree trunks. Because of the uneven structure of
wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
, a wheel made from a horizontal slice of a tree trunk will tend to be inferior to one made from rounded pieces of longitudinal boards. The spoked wheel was invented more recently and allowed the construction of lighter and swifter vehicles. The earliest known examples of wooden spoked wheels are in the context of the
Sintashta culture The Sintashta culture (russian: Синташтинская культура, Sintashtinskaya kul'tura), around 2050–1900 BCE, is the first phase of the Sintashta–Petrovka culture. or Sintashta–Arkaim culture,. and is a late Middle Bronze Ag ...
, dating to c. 2000 BCE (
Krivoye Lake Krivoye Ozero is a small lake in the Chelyabinsk Oblast of Russia, southeast of Magnitogorsk, near the Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly i ...
). Soon after this, horse cultures of the
Caucasus The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia (country), Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range ...
region used horse-drawn spoked-wheel war chariots for the greater part of three centuries. They moved deep into the Greek peninsula where they joined with the existing Mediterranean peoples to give rise, eventually, to classical Greece after the breaking of
Minoan The Minoan civilization was a Bronze Age Aegean civilization on the island of Crete and other Aegean Islands, whose earliest beginnings were from 3500BC, with the complex urban civilization beginning around 2000BC, and then declining from 1450B ...
dominance and consolidations led by pre-classical
Sparta Sparta ( Doric Greek: Σπάρτα, ''Spártā''; Attic Greek: Σπάρτη, ''Spártē'') was a prominent city-state in Laconia, in ancient Greece. In antiquity, the city-state was known as Lacedaemon (, ), while the name Sparta referre ...
and
Athens Athens ( ; el, Αθήνα, Athína ; grc, Ἀθῆναι, Athênai (pl.) ) is both the capital and largest city of Greece. With a population close to four million, it is also the seventh largest city in the European Union. Athens dominates ...
. Celtic chariots introduced an
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
rim around the wheel in the 1st millennium BCE. In China, wheel tracks dating to around 2200 BCE have been found at Pingliangtai, a site of the
Longshan Culture The Longshan (or Lung-shan) culture, also sometimes referred to as the Black Pottery Culture, was a late Neolithic culture in the middle and lower Yellow River valley areas of northern China from about 3000 to 1900 BC. The first archaeological fi ...
. Similar tracks were also found at
Yanshi Yanshi District () is a district in the prefecture-level city of Luoyang in western Henan province, China. Yanshi lies on the Luo River and is the easternmost county-level division of Luoyang. History After the Zhou conquest of Shang in mid-11th ...
, a city of the
Erlitou culture The Erlitou culture was an early Bronze Age urban society and archaeological culture that existed in the Yellow River valley from approximately 1900 to 1500 BC. A 2007 study of radiocarbon dating proposed a narrower date range of 1750 to 1530 B ...
, dating to around 1700 BCE. The earliest evidence of spoked wheels in China comes from
Qinghai Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also known as Kokonor, is a landlocked province in the northwest of the People's Republic of China. It is the fourth largest province of China by area and has the third smallest po ...
, in the form of two wheel hubs from a site dated between 2000 and 1500 BCE. In Britain, a large wooden wheel, measuring about in diameter, was uncovered at the
Must Farm Part of a Bronze Age settlement was uncovered at Must Farm quarry, at Whittlesey, near Peterborough, in Cambridgeshire, England. The site has been described as "Britain's Pompeii" due to its relatively good condition, including the "best-preser ...
site in East Anglia in 2016. The specimen, dating from 1,100 to 800 BCE, represents the most complete and earliest of its type found in Britain. The wheel's hub is also present. A horse's spine found nearby suggests the wheel may have been part of a horse-drawn cart. The wheel was found in a settlement built on stilts over wetland, indicating that the settlement had some sort of link to dry land. Although large-scale use of wheels did not occur in the Americas prior to European contact, numerous small wheeled artifacts, identified as children's toys, have been found in Mexican archeological sites, some dating to approximately 1500 BCE. Some argue that the primary obstacle to large-scale development of the wheel in the Americas was the absence of domesticated large animals that could be used to pull wheeled carriages. The closest relative of
cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult ma ...
present in Americas in pre-Columbian times, the
American bison The American bison (''Bison bison'') is a species of bison native to North America. Sometimes colloquially referred to as American buffalo or simply Bubalina, buffalo (a different clade of bovine), it is one of two extant species of bison, alongs ...
, is difficult to domesticate and was never domesticated by Native Americans; several horse species existed until about 12,000 years ago, but ultimately became extinct. The only large animal that was domesticated in the Western hemisphere, the
llama The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a meat and pack animal by Andean cultures since the Pre-Columbian era. Llamas are social animals and live with others as a herd. Their wool is soft ...
, a pack animal, was not physically suited to use as a draft animal to pull wheeled vehicles, and use of the llama did not spread far beyond the
Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
by the time of the arrival of Europeans. On the other hand,
Mesoamerica Mesoamerica is a historical region and cultural area in southern North America and most of Central America. It extends from approximately central Mexico through Belize, Guatemala, El Salvador, Honduras, Nicaragua, and northern Costa Rica ...
ns never developed the
wheelbarrow A wheelbarrow is a small hand-propelled vehicle, usually with just one wheel, designed to be pushed and guided by a single person using two handles at the rear, or by a sail to push the ancient wheelbarrow by wind. The term "wheelbarrow" is ma ...
, the
potter's wheel In pottery, a potter's wheel is a machine used in the shaping (known as throwing) of clay into round ceramic ware. The wheel may also be used during the process of trimming excess clay from leather-hard dried ware that is stiff but malleable, a ...
, nor any other practical object with a wheel or wheels. Although present in a number of toys, very similar to those found throughout the world and still made for children today ("pull toys"), the wheel was never put into practical use in Mesoamerica before the 16th century. Possibly the closest the Mayas came to the utilitarian wheel is the spindle whorl, and some scholars believe that these toys were originally made with spindle whorls and spindle sticks as "wheels" and "axes".
Aboriginal Australians Aboriginal Australians are the various Indigenous peoples of the Australian mainland and many of its islands, such as Tasmania, Fraser Island, Hinchinbrook Island, the Tiwi Islands, and Groote Eylandt, but excluding the Torres Strait Isl ...
traditionally used circular discs rolled along the ground for use as target practice.
Nubia Nubia () (Nobiin: Nobīn, ) is a region along the Nile river encompassing the area between the first cataract of the Nile (just south of Aswan in southern Egypt) and the confluence of the Blue and White Niles (in Khartoum in central Sudan), or ...
ns from after about 400 BCE used wheels for spinning
pottery Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and ...
and as
water wheels A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel (usually constructed from wood or metal), with a number of blades or bucket ...
. It is thought that Nubian waterwheels may have been ox-driven. It is also known that Nubians used horse-drawn chariots imported from
Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...
. Starting from the 18th century in West Africa, wheeled vehicles were mostly used for ceremonial purposes in places like Dahomey. The wheel was barely used for transportation, with the exception of
Ethiopia Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
and
Somalia Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of SomaliaThe ''Federal Republic of Somalia'' is the country's name per Article 1 of thProvisional Constituti ...
in Sub-Saharan Africa well into the 19th century. The spoked wheel was in continued use without major modification until the 1870s, when wire-spoked wheels and pneumatic tires were invented. Pneumatic tires can greatly reduce rolling resistance and improve comfort. Wire spokes are under tension, not compression, making it possible for the wheel to be both stiff and light. Early radially-spoked wire wheels gave rise to tangentially-spoked wire wheels, which were widely used on cars into the late 20th century. Cast
alloy wheels In the automotive industry, alloy wheels are wheels that are made from an alloy of aluminium or magnesium. Alloys are mixtures of a metal and other elements. They generally provide greater strength over pure metals, which are usually much softe ...
are now more commonly used; forged alloy wheels are used when weight is critical. The invention of the wheel has also been important for
technology Technology is the application of knowledge to reach practical goals in a specifiable and Reproducibility, reproducible way. The word ''technology'' may also mean the product of such an endeavor. The use of technology is widely prevalent in me ...
in general, important applications including the
water wheel A water wheel is a machine for converting the energy of flowing or falling water into useful forms of power, often in a watermill. A water wheel consists of a wheel (usually constructed from wood or metal), with a number of blades or bucket ...
, the cogwheel (see also
antikythera mechanism The Antikythera mechanism ( ) is an Ancient Greek hand-powered orrery, described as the oldest example of an analogue computer used to predict astronomical positions and eclipses decades in advance. It could also be used to track the four-yea ...
), the
spinning wheel A spinning wheel is a device for spinning thread or yarn from fibres. It was fundamental to the cotton textile industry prior to the Industrial Revolution. It laid the foundations for later machinery such as the spinning jenny and spinning f ...
, and the astrolabe or
torquetum The ''torquetum'' or turquet is a medieval astronomical instrument designed to take and convert measurements made in three sets of coordinates: Horizon, equatorial, and ecliptic. It is said to be a combination of Ptolemy's astrolabon and the p ...
. More modern descendants of the wheel include the propeller, the jet engine, the
flywheel A flywheel is a mechanical device which uses the conservation of angular momentum to store rotational energy; a form of kinetic energy proportional to the product of its moment of inertia and the square of its rotational speed. In particular, as ...
( gyroscope) and the
turbine A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating ...
.


Mechanics and function

A wheeled vehicle requires much less work to move than simply dragging the same weight. The low resistance to motion is explained by the fact that the frictional work done is no longer at the surface that the vehicle is traversing, but in the bearings. In the simplest and oldest case the bearing is just a round hole through which the axle passes (a "
plain bearing A plain bearing, or more commonly sliding contact bearing and slide bearing (in railroading sometimes called a solid bearing, journal bearing, or friction bearing), is the simplest type of bearing, comprising just a bearing surface and no roll ...
"). Even with a plain bearing, the frictional work is greatly reduced because: * The normal force at the sliding interface is same as with simple dragging. * The sliding distance is reduced for a given distance of travel. * The coefficient of friction at the interface is usually lower. Example: * If a 100 kg object is dragged for 10 m along a surface with the
coefficient of friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of t ...
''μ'' = 0.5, the
normal force In mechanics, the normal force F_n is the component of a contact force that is perpendicular to the surface that an object contacts, as in Figure 1. In this instance '' normal'' is used in the geometric sense and means perpendicular, as oppos ...
is 981 N and the
work Work may refer to: * Work (human activity), intentional activity people perform to support themselves, others, or the community ** Manual labour, physical work done by humans ** House work, housework, or homemaking ** Working animal, an animal t ...
done (required
energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...
) is (work=force x distance) 981 × 0.5 × 10 = 4905
joule The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force applie ...
s. * Now give the object 4 wheels. The normal force between the 4 wheels and axles is the same (in total) 981 N. Assume, for wood, ''μ'' = 0.25, and say the wheel
diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...
is 1000 mm and axle diameter is 50 mm. So while the object still moves 10 m the sliding frictional surfaces only slide over each other a distance of 0.5 m. The work done is 981 × 0.25 × 0.5 = 123 joules; the work done has reduced to 1/40 of that of dragging. Additional energy is lost from the wheel-to-road interface. This is termed rolling resistance which is predominantly a deformation loss. It depends on the nature of the ground, of the material of the wheel, its inflation in the case of a tire, the net torque exerted by the eventual engine, and many other factors. A wheel can also offer advantages in traversing irregular surfaces if the wheel radius is sufficiently large compared to the irregularities. The wheel alone is not a machine, but when attached to an axle in conjunction with bearing, it forms the
wheel and axle The wheel and axle is a simple machine consisting of a wheel attached to a smaller axle so that these two parts rotate together in which a force is transferred from one to the other. The wheel and axle can be viewed as a version of the lever, wi ...
, one of the
simple machine A simple machine is a mechanical device that changes the direction or magnitude of a force. In general, they can be defined as the simplest mechanisms that use mechanical advantage (also called leverage) to multiply force. Usually the term ref ...
s. A driven wheel is an example of a wheel and axle. Wheels pre-date driven wheels by about 6000 years, themselves an evolution of using round logs as rollers to move a heavy load—a practice going back in pre-history so far that it has not been dated.


Construction


Rim

The rim is the "outer edge of a wheel, holding the tire". It makes up the outer circular design of the wheel on which the inside edge of the
tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which t ...
is mounted on vehicles such as
automobile A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarde ...
s. For example, on a bicycle wheel the rim is a large hoop attached to the outer ends of the spokes of the wheel that holds the tire and tube. In the 1st millennium BCE an
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
rim was introduced around the wooden wheels of chariots.


Hub

The hub is the center of the wheel, and typically houses a bearing, and is where the spokes meet. A
hubless wheel A centreless wheel is a wheel that lacks a centre or hub, instead being supported and driven at the rim. Design Centreless wheels are toroidal in shape and have one or multiple bearings along the rim. Propulsion can be achieved in diffe ...
(also known as a rim-rider or centerless wheel) is a type of wheel with no center hub. More specifically, the hub is actually almost as big as the wheel itself. The axle is hollow, following the wheel at very close tolerances.


Spokes

A ''spoke'' is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface. The term originally referred to portions of a log which had been split lengthwise into four or six sections. The radial members of a wagon wheel were made by carving a spoke (from a log) into their finished shape. A
spokeshave A spokeshave is a hand tool used to shape and smooth woods in woodworking jobs such as making cart wheel spokes, chair legs, paddles, bows, and arrows. The tool consists of a blade fixed into the body of the tool, which has a handle for each ha ...
is a
tool A tool is an object that can extend an individual's ability to modify features of the surrounding environment or help them accomplish a particular task. Although many animals use simple tools, only human beings, whose use of stone tools dates ba ...
originally developed for this purpose. Eventually, the term spoke was more commonly applied to the finished product of the
wheelwright A wheelwright is a craftsman who builds or repairs wooden wheels. The word is the combination of "wheel" and the word "wright", (which comes from the Old English word "''wryhta''", meaning a worker or shaper of wood) as in shipwright and arkwr ...
's work, than to the materials used.


Wire

The rims of ''wire wheels'' (or "wire spoked wheels") are connected to their hubs by wire spokes. Although these
wire Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible strand of metal. Wire is c ...
s are generally stiffer than a typical
wire rope Steel wire rope (right hand lang lay) Wire rope is several strands of metal wire twisted into a helix forming a composite ''rope'', in a pattern known as ''laid rope''. Larger diameter wire rope consists of multiple strands of such laid rope in a ...
, they function mechanically the same as tensioned flexible wires, keeping the rim true while supporting applied loads. Wire wheels are used on most bicycles and still used on many
motorcycles A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...
. They were invented by aeronautical engineer George Cayley and first used in bicycles by
James Starley James Starley (21 April 1830 – 17 June 1881) was an English inventor and father of the bicycle industry. He was one of the most innovative and successful builders of bicycles and tricycles. His inventions include the differential gear and t ...
. A process of assembling wire wheels is described as
wheelbuilding Wheelbuilding is the process of assembling wire wheels (generally a bicycle wheel, but including wheelchairs, and some cars). The components of a wire wheel are the rim, spokes, nipples, and hub. Goals The wheelwright must ensure that the ...
.


Tire/Tyre

A tire (in
American English American English, sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. English is the most widely spoken language in the United States and in most circumstances i ...
and Canadian English) or tyre (in some
Commonwealth Nations The Commonwealth of Nations, simply referred to as the Commonwealth, is a political association of 56 member states, the vast majority of which are former territories of the British Empire. The chief institutions of the organisation are the Co ...
such as UK,
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
,
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
, Australia and
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
) is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground. The word itself may be derived from the word "tie", which refers to the outer steel ring part of a wooden cart wheel that ties the wood segments together (see
Etymology Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...
above). The fundamental materials of modern tires are synthetic rubber,
natural rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...
, fabric, and wire, along with other compound chemicals. They consist of a tread and a body. The tread provides traction while the body ensures support. Before rubber was invented, the first versions of tires were simply bands of metal that fitted around wooden wheels to prevent wear and tear. Today, the vast majority of tires are pneumatic inflatable structures, comprising a doughnut-shaped body of cords and wires encased in rubber and generally filled with compressed air to form an inflatable cushion. Pneumatic tires are used on many types of vehicles, such as cars, bicycles,
motorcycles A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...
,
truck A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame constructi ...
s, earthmovers, and
aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engine ...
.


Protruding or covering attachments

Extreme Off-roading, off-road conditions have resulted in the invention of several types of wheel cover, which may be constructed as removable attachments or as permanent covers. Wheels like this are no longer necessarily round, or have panels that make the ground-contact area flat. Examples include: *Snow chains - Specially designed chain assemblies that wrap around the tire to provide increased grip, designed for deep snow. *Dreadnaught wheel - A type of permanently attached hinged panels for general extreme off-road use. These are not connected directly to the wheels, but to each other. *Pedrail wheel - A system of rails that holds panels that hold the vehicle. These do not necessarily have to be built as a circle (wheel) and are thus also a form of Continuous track. *A version of the above examples (name unknown to the writer) was commonly used on heavy artillery during World War I. Specific examples: Cannone da 149/35 A and the Big Bertha (howitzer), Big Bertha. These were panels that were connected to each other by multiple hinges and could be installed over a contemporary wheel. *Continuous track - A system of linked and hinged chains/panels that cover multiple wheels in a way that allows the vehicles mass to be distributed across the space between wheels that are positioned in front of / behind other wheels. *"Tire totes" - A bag designed to cover a tire to improve traction in deep snow. Truck and bus wheels may block (stop rotating) under certain circumstances, such as brake system failure. To help detect this, they sometimes feature "wheel rotation indicators": colored strips of plastic attached to the rim and protruding out from it, such that they can be seen by the driver in the Side-view mirror, side-view mirrors. These devices were invented and patented in 1998 by a Canadian truck shop owner.


Alternatives

While wheels are very widely used for ground transport, there are alternatives, some of which are suitable for terrain where wheels are ineffective. Alternative methods for ground transport without wheels include: *Maglev *Sled, ski or travois *Hovercraft and ekranoplans *Walking pedestrian, Litter (vehicle) or a Walker (machine), walking machine *Horse riding *Continuous track, Caterpillar tracks (operated by wheels) *Pedrail wheels, using aspects of both wheel and caterpillar track *Spheres, as used by Dyson (company), Dyson vacuum cleaners and hamster balls *Screw-propelled vehicle


Symbolism

The wheel has also become a strong cultural and spiritual metaphor for a cycle or regular repetition (see chakra, reincarnation, Yin and yang, Yin and Yang among others). As such and because of the difficult terrain, wheeled vehicles were forbidden in history of Tibet, old Tibet. The wheel in ancient China is seen as a symbol of health and strength and used by some villages as a tool to predict future health and success. The
diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...
of the wheel is indicator of one's future health. The Kalachakra or wheel of time is also a subject in some forms of Buddhism, along with the dharmachakra.John C. Huntington, Dina Bangdel, ''The Circle of Bliss: Buddhist Meditational Art,'' p. 524.
The winged wheel is a symbol of progress, seen in many contexts including the coat of arms of Panama, the logo of the Ohio State Highway Patrol and the State Railway of Thailand. The wheel is also the prominent figure on the flag of India. The wheel in this case represents law (dharma). It also appears in the flag of the Romani people, hinting to their nomadic history and their Indian origins. The introduction of spoked ( chariot) wheels in the Middle Bronze Age appears to have carried somewhat of a prestige. The sun cross appears to have a significance in Bronze Age religion (disambiguation), Bronze Age religion, replacing the earlier concept of a Solar barge, solar barge with the more 'modern' and technologically advanced solar chariot. The wheel was also a solar symbol for the Ancient Egyptians. In modern usage, the 'invention of the wheel' can be considered as a symbol of one of the first technologies of early civilization, alongside farming and metalwork, and thus be used as a benchmark to grade the level of societal progress. Some Modern Paganism, Neopagans such as Wiccans have adopted the Wheel of the Year into their religious practices.


See also

* Types: Alloy wheel, Artillery wheel, Ball transfer unit, Bicycle wheel, Caster, Gear, Cogwheel, Dreadnaught wheel, Driving wheel, Flywheel, Hubless wheel, Inline skates#Wheels, Inline skate wheel, Mansell wheel, Mecanum wheel, Motorcycle wheel, Omni wheel, Pedrail wheel, Disteel, Pressed Steel wheel, Skateboard#Wheels, Skateboard wheel, Square wheel, Stairclimber#Stairclimber wheels, Stairclimber wheel, Steering wheel (Ship's wheel), Train wheel, Tweel, Wagon wheel (transportation), Wagon wheel, Wire wheel * Components: Axle, Bogie/Skateboard truck, Truck, Differential (mechanical device), Differential, Drive shaft, Drivetrain, Rim (wheel), Rim, Snow chains, Spoke, Tire, Wheelset (rail transport), Wheelset * Related technologies and concepts: Archimedes screw, Barrel, Breaking wheel, Color wheel, Compact disc, Ferris wheel, Pottery wheel, Propeller, Reinventing the wheel, Spindle whorl, Trackball, Wagon-wheel effect, Water wheel, Wheelbarrow, Wheelie, Wheel of Fortune (disambiguation), Wheel of Fortune, Wheelwright, Windlass, Windmill * Alternatives: Hovercraft, Air cushion, Continuous track, Screw-propelled vehicle, Counter-rotating screws, Leg mechanism, Magnetic levitation, Wing-in-ground-effect * History: History of the wheel in Africa, ''The Horse, The Wheel and Language'', Rotating locomotion in living systems, Terrestrial locomotion in animals#Rolling, Terrestrial locomotion in animals: Rolling, Robot locomotion * Theory: Rolling resistance, Rotational energy, Torque, Wheel and axle, Wheel and axle (simple machine), Wheel sizing


References


External links

* University of Kiel.
3400 BC: The oldest evidence for the use of the wheel and wagon originates from Northern Germany
. Online: April 11th, 2022. Retrieved: April 14th, 2022. {{Authority control Wheels, Iraqi inventions Mesopotamian inventions