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A centreless wheel is a
wheel A wheel is a circular component that is intended to rotate 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 machines. Wheels, in conjunction wi ...
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 different ways, such as with
gear teeth A gear is a rotating circular machine part having cut teeth or, in the case of a cogwheel or gearwheel, inserted teeth (called ''cogs''), which mesh with another (compatible) toothed part to transmit (convert) torque and speed. The basic p ...
along the inner surface of the rim. They can be made lighter than solid and spoked wheels, resulting in better handling and less rotational inertia. The lack of spokes or a traditional hub also allows for more space, which can be used to more easily package a
hub motor The wheel hub motor (also called wheel motor, wheel hub drive, hub motor or in-wheel motor) is an electric motor that is incorporated into the hub of a wheel and drives it directly. History * First wheel motor concept: Wellington Adams of ...
. While Franco Sbarro was the first to replace vehicles' conventional wheels with hubless wheels in 1989, monowheels, which are similar in practice, predate Sbarro's hubless-wheel vehicles by more than 100 years. The
research and development Research and development (R&D or R+D), known in Europe as research and technological development (RTD), is the set of innovative activities undertaken by corporations or governments in developing new services or products, and improving existi ...
of centreless wheels has not been pursued by any large company due to their complexity, with their use limited to small companies and scientific analyses.


Examples


''Tron: Legacy'' Light Cycle replica

One real-life example of hubless wheels are those used in the replica '' Tron: Legacy'' Light Cycle. The street-legal
motorcycle 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 ...
was modelled after the vehicle from the film and sold through
Hammacher Schlemmer Hammacher Schlemmer is an American retailer and catalog company based in Niles, Illinois. History Hammacher Schlemmer began as a hardware store specializing in hard-to-find tools in the Bowery district of New York City in 1848. Owned by pro ...
. Its hubless wheels are made from former truck tires, and a chain-driven friction drum provides power and brake force. Designed "for casual cruising and slow ride-bys at shows", it consists of a
fuel-injected Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All compr ...
Suzuki is a Japan, Japanese multinational corporation headquartered in Minami-ku, Hamamatsu, Japan. Suzuki manufactures automobiles, motorcycles, All-terrain vehicle, all-terrain vehicles (ATVs), outboard motor, outboard marine engines, wheelchairs ...
4-stroke A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directio ...
engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gen ...
in a steel frame covered by a fiberglass body with
electroluminescent wire Electroluminescent wire (often abbreviated as EL wire) is a thin copper wire coated in a phosphor that produces light through electroluminescence when an alternating current is applied to it. It can be used in a wide variety of applicationsā ...
lighting.


Skatecycle

The
Skatecycle The Skatecycle, also known as the "Freerider Skatecycle", is the world's first mass-produced Centreless wheel, hubless, self-propelled skate. Invented and patented by Alon Karpman, the Skatecycle was manufactured by Brooklyn Workshop, Inc. based ...
is a device similar to a
caster board A caster board, vigorboard or waveboard is a two-wheeled, human-powered land vehicle. Other names are J-board and RipStik (sometimes written ripstick or rip stick), both of which are derived from commercial brands. A caster board has two narrow ...
, but with hubless wheels and a 2-axis twisting
axle 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, bearing ...
replacing the function of the casters. The central axle connects two standing platforms surrounded by 9"
polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethan ...
hubless wheels, giving said wheels the appearance of
stirrup A stirrup is a light frame or ring that holds the foot of a rider, attached to the saddle by a strap, often called a ''stirrup leather''. Stirrups are usually paired and are used to aid in mounting and as a support while using a riding animal ( ...
s. In order to move the unit, the rider rotates their feet inwards and outwards, creating a wave-like motion in the hinged frame and providing propulsion. In recognition of its novel design, the Skatecycle received the Bronze International Design Excellence Award in the transportation category in 2010.


Zero Bike

Another example of a vehicle with centreless wheels is the Zero Bike, a lightweight hubless
bicycle A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist. Bic ...
whose non-functional prototype won an
Industrial Design Excellence Award The International Design Excellence Awards (IDEA) is an award program previously co-sponsored by ''BusinessWeek'' magazine, and in 2010 ''Fast Company'' magazine and the Industrial Designers Society of America (IDSA). According to the IDSA, IDEA "i ...
in 1991. Designed by then-
ArtCenter College of Design Art Center College of Design (stylized as ArtCenter College of Design) is a private art college in Pasadena, California. History ArtCenter College of Design was founded in 1930 in downtown Los Angeles as the Art Center School. In 1935, Fred ...
students Makota Makita and Hiroshi Tsuzaki, it is based on the principle of magnetic
superconductivity Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...
, also used in high-speed maglev trains.


Ujet One

The Ujet One electric scooter, produced in Luxembourg since 2019, features front and rear centreless wheels connected to its frame with torsion-sprung suspension, as well as an electric hub motor. Such a setup is communicated to benefit from minimal energy loss in transmission. In 2019, the One won both the iF Gold and
Red Dot The Red Dot Design Award is a German international design prize awarded by Red Dot GmbH & Co. KG. There are prize categories for product design, brands and communication design, and design concept. Since 1955, designers and producers can apply ...
awards for its design.


Freedom Sprints motorcycle

A working prototype of a centreless wheel, using
ball bearings A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this ...
, was shown at India Bike Week 2014 in
Goa Goa () is a state on the southwestern coast of India within the Konkan region, geographically separated from the Deccan highlands by the Western Ghats. It is located between the Indian states of Maharashtra to the north and Karnataka to the ...
. Attached to a customized
Royal Enfield Royal Enfield was a brand name under which The Enfield Cycle Company Limited of Redditch, Worcestershire sold motorcycles, bicycles, lawnmowers and stationary engines which they had manufactured. Enfield Cycle Company also used the brand name "E ...
motorcycle, the prototype rear wheel was designed by a team by the name of Freedom Sprints, which included Abhishek Sharma, Ankur Tiwari, Sarvesh Khemka, Yashodeep Yadav, and Mohammed Ansar. During testing, the bike was ridden from
Ajmer Ajmer is one of the major and oldest cities in the Indian state of Rajasthan and the centre of the eponymous Ajmer District. It is located at the centre of Rajasthan. It is also known as heart of Rajasthan. The city was established as "''Aj ...
to
Jaipur Jaipur (; Hindi Language, Hindi: ''Jayapura''), formerly Jeypore, is the List of state and union territory capitals in India, capital and largest city of the Indian States and union territories of India, state of Rajasthan. , the city had a pop ...
.


See also

*
Hub-center steering Hub-center steering (HCS) is one of several different types of front-end suspension/steering mechanisms used in motorcycles and cargo bicycles. Hub-center steering is characterized by the steering pivot points being inside the hub of the wheel, ra ...
*
Motorcycle wheel Motorcycle wheels are made to cope with radial and axial forces. They also provide a way of mounting other critical components such as the brakes, final drive and suspension. Wheels, and anything directly connected to them, are considered to be un ...


References

{{Reflist Wheels