Wheel construction refers to the making of

wheels A wheel is a rotating component (typically circular in shape) that is intended to turn on an axle bearing. The wheel is one of the key components of the wheel and axle which is one of the six simple machines. Wheels, in conjunction with axl ...

. Construction of wire-spoked wheels is generally termed as

wheelbuilding Wheelbuilding is the process of assembling wire wheels (generally a bicycle wheel, but including wheelchairs, and some automobile, cars and motorcycles). The components of a wire wheel are the Rim_(wheel), rim, spokes, spoke nipple, nipples, and ...

, so wheel construction refers to construction of non-wire wheels, e.g. wheels of cars and other heavier vehicles. Wheels are constructed in a wide variety of designs using different materials, but in the early 21st century,

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

and

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

are most often used, with steel-made wheels being heavier and more durable than aluminum wheels. The performance of a wheel depends on the alloy and technique used to construct it. A wheel is usually made up of a rim, which connects with the tire, and a central disc, also known as the disc or spider, which connects the wheel to the vehicle. Wheels are usually of two types: semi-drop center (SDC), used in trucks, and drop center (DC), used in other vehicles.

History of wheel construction

The

wheel A wheel is a rotating component (typically circular in shape) that is intended to turn on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machin ...

is one of the most important inventions, but its inventor and exact date of invention are not yet known. The oldest known wheel was excavated from

Mesopotamia Mesopotamia is a historical region of West Asia situated within the Tigris–Euphrates river system, in the northern part of the Fertile Crescent. Today, Mesopotamia is known as present-day Iraq and forms the eastern geographic boundary of ...

, believed to be 5500 years old. This earliest wheel was a

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, ...

, used in the city of Ur in

(present-day

Iraq Iraq, officially the Republic of Iraq, is a country in West Asia. It is bordered by Saudi Arabia to Iraq–Saudi Arabia border, the south, Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq border, the east, the Persian Gulf and ...

), invented by Mesopotamians (also known as Sumerians) around 3500

BCE Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the o ...

. The earliest known use of the wheel for transportation is in Mesopotamian chariots about 3200 years ago. Egyptians developed wheels with spokes about 2000 years ago, followed by Europeans some 1400 years ago. Another source says the oldest wheel used for transportation, with a radius of 27.5 inches (70 centimeters), was discovered in 2002, about 12.5 miles (20 kilometres) south west of

Ljubljana {{Infobox settlement , name = Ljubljana , official_name = , settlement_type = Capital city , image_skyline = {{multiple image , border = infobox , perrow = 1/2/2/1 , total_widt ...

Slovenia Slovenia, officially the Republic of Slovenia, is a country in Central Europe. It borders Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and a short (46.6 km) coastline within the Adriati ...

, and is believed to be 5200 years old.

Methods of single-piece wheel construction

Most wheels are single-piece wheels, made using

casting Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or ...

forging Forging is a manufacturing process involving the shaping of metal using localized compression (physics), compressive forces. The blows are delivered with a hammer (often a power hammer) or a die (manufacturing), die. Forging is often classif ...

, rim rolling and/or high light methods.

Casting

In casting, wheels are made by using a mold. The mold is filled with molten metal; as the metal cools, the wheel becomes strong and rigid. Various types of casting processes result in wheels with different properties. Gravity casting and low-pressure casting are common types of casting.

Gravity casting

In gravity casting, metal is poured into a mold and gravity alone causes the molten metal to fill the mold. This method is simple and low-cost, but

cast this way will not be as dense as with other casting methods. Wheels constructed by this method are therefore made slightly heavier to achieve equivalent strength.

Low-pressure casting

In this method, molten aluminum is pumped into molds at heightened speed, which increases pressure and prevents formation of bubbles. Low-pressure casting is most common type of wheel casting because of the strength and quality of wheels formed by this method.

Forging

The forging method is considered best for making single-piece wheels because the wheels made using this method are both lightweight and strong. In this method, a stronger and denser wheel is produced by shaping an aluminum

billet In European militaries, a billet is a living-quarters to which a soldier is assigned to sleep. In American usage, it refers to a specific personnel position, assignment, or duty station to which a soldier can be assigned. Historically, a billet w ...

under high heat and at about 900 bars of pressure.

Rim-rolling

In this method, simple casting and a special rolling machine are used to construct wheels. The desired wheel is molded by heating its outer portion, with pressure provided by spinning the unfinished wheel, and sculpting the wheel using specialized rollers. This method creates a wheel similar in quality to forged wheels, but at a lower cost. OEM (original equipment manufacturing) wheels constructed by this method are used in special performance vehicles.

High light technology

This method is used to construct light wheels of racing vehicles. In this method, the material is compressed using rollers along a low-pressure aluminum barrel, which gives it its required shape and form.

Methods of multi-piece wheel construction

Two- or three-piece wheels, also known as multi-piece wheels, are assembled from pieces constructed separately by the methods mentioned above. Bolts or

welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, primarily by using high temperature to melting, melt the parts together and allow them to cool, causing Fusion welding, fusion. Co ...

, or both, can be used to assemble the separate parts of such wheels.

References

{{Reflist Wheels