A quick release skewer is a mechanism for attaching 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 ...

to a

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 ...

. It consists of a rod threaded on one end and with a lever operated

cam Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the bin ...

assembly on the other. The rod is inserted into the hollow

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 ...

of the wheel, a special nut is threaded on, and the lever is closed to tighten the cam and secure the wheel to the fork. Wheels equipped with quick release mechanisms can be removed from the

bicycle frame A bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles: a main triangl ...

and replaced without using tools by opening and closing the cam lever, thus more quickly than wheels with solid axles and nuts. On the negative side, a quick-release hub renders a wheel more vulnerable to theft and care must be taken to ensure that the mechanism is properly tightened. Similar quick-release mechanisms are also used to operate

seatpost A bicycle seatpost, seatpin, saddlepole, saddle pillar, or saddle pin is a tube that extends upwards from the bicycle frame to the saddle. The amount that it extends out of the frame can usually be adjusted, and there is usually a mark that indic ...

clamps, and the collapsing stem of

folding bicycle A folding bicycle is a bicycle designed to fold into a compact form, facilitating transport and storage. When folded, the bikes can be more easily carried into buildings, on public transportation (facilitating mixed-mode commuting and bicycl ...

s and

kick scooter A kick scooter (also referred to as a push-scooter or scooter) is a human-powered street vehicle with a handlebar, deck, and wheels propelled by a rider pushing off the ground with their leg. Today the most common scooters are made of aluminum, ...

History

The mechanism was invented in 1927 by

Tullio Campagnolo Gentullio Campagnolo (26 August 1901 – 3 February 1983) was an Italian racing cyclist and inventor who patented the quick release skewer, as well as founder of the bicycle component company Campagnolo. Many professional cyclists have used Ca ...

, an

Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...

bicycle racer. He was frustrated when he attempted to change gears during a race. At the time there was but one cog on each side of the rear hub, so gear changes necessitated stopping, removing the rear wheel, flipping it over horizontally so that the opposite cog is engaged by the chain, and finally reinstalling the wheel. The weather had turned cold, and his hands were numb, so he could not operate the

wingnuts ''WingNuts: Temporal Navigator'' is a 2001 top-down multi-directional shooter for Macintosh made by Freeverse Software. It was inspired by arcade games ''Time Pilot'' and ''1942.'' In ''WingNuts'', the player navigates an aircraft around a two-di ...

which retained the wheel. He had been well-placed prior to the gear change, but lost valuable time. This prompted him to develop the quick release. Another Campagnolo invention that made use of the quick-release mechanism was the Cambio Corsa, a multi-gear changing system consisting of a rear wheel quick-release lever with a mechanical extension that placed the lever itself near the bicycle's saddle, combined with a fork that served as a primitive version of a rear derailleur (without idler pulleys to take up slack), that also had a control lever near the bicycle saddle. This innovation enabled bicycle riders quickly to change gears while in motion by releasing the axle, moving the rear wheel slightly forward by applying tension to the chain, actuating the fork to change to a larger sprocket, and tightening the quick release again; or else releasing the axle, actuating the fork to change to a smaller sprocket, moving the wheel slightly rearward by braking, and tightening the quick release again. The quick-release mechanism, along with other innovations and high standards of manufacture, enabled

Campagnolo Campagnolo is an Italian manufacturer of high-end bicycle components with headquarters in Vicenza, Italy. The components are organised as groupsets (gruppi), and are a near-complete collection of a bicycle's mechanical parts. Campagnolo's flagsh ...

to become a leading

road cycling Road cycling is the most widespread form of cycling in which cyclists ride on paved roadways. It includes Recreational cycling, recreational, Road bicycle racing, racing, Bicycle commuting, commuting, and utility cycling. As users of the road, ...

and

track cycling Track cycling is a bicycle racing sport usually held on specially built banked tracks or velodromes using purpose-designed track bicycles. History Track cycling has been around since at least 1870. When track cycling was in its infancy, it wa ...

component manufacturer.

Use

Quick releases tend not to be used on certain types of bicycles, such as

utility bicycles A utility bicycle, city bicycle, urban bicycle, European city bike (ECB), Dutch bike, classic bike or simply city-bike, is a bicycle designed for frequent very short, very slow rides through very flat urban areas. It is a form of utility bicycle ...

(with a single speed or

hub gears A hub gear, internal-gear hub, internally geared hub or just gear hub is a gear ratio changing system commonly used on bicycles that is implemented with planetary or epicyclic gears. The gears and lubricants are sealed within the shell of the h ...

) or

track bicycle A track bicycle or track bike is a bicycle optimized for racing at a velodrome or outdoor track. Unlike road bicycles, the track bike is a fixed-gear bicycle; thus, it has only a single gear ratio and has neither a freewheel nor brakes. Tires are ...

s, partly because of tradition and partly because there is less need for quick removal of wheels without using tools. Quick releases are sometimes recommended against with the use of

disc brakes A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or a "rotor" to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hol ...

because of the need for the axle attachment to withstand braking forces. Skewers of French origin differed in threading, as all other specifications of a French bicycle once were, as they were based on the Metric System. Despite modern measurements for bicycles being given in metric units, they are based on the United States Customary System (derived from English Units), ie, 28.6≈1 1/8. Over the years quick release mechanisms have been adopted as the primary wheel release devices by the average rider. However, as

Sheldon Brown (bicycle mechanic) Sheldon Brown (July 14, 1944 – February 4, 2008) was an American bicycle mechanic, technical expert and author. He contributed to print and online sources related to bicycling and bicycle mechanics, in particular the web site ''Sheldon Brown's B ...

notes this change has come with some difficulty: The debate over quick release use as illustrated by Brown, has become a national issue due to several lawsuits brought on by various people including a group of mothers who claim their children were injured due to innocently incorrect use of quick releases. The quick-release levers are usually on the left side of the bike, though some prefer to have them on the right if a disc brake is on the left. Mountain bikers often prefer to point the lever backwards, to reduce the risk of it catching on undergrowth and being pulled open.Bicycling Life
Lever points rearward

Variations

Locking skewers are available without handles or with specialty removable handles in order to deter wheel theft.

References

External links

Article on Quick release skewers
by Sheldon Brown {{Bike equipment Bicycle parts Italian inventions Kick scooters