Bicycle pedal
Overview
 
A bicycle pedal is the part of a bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

 that the rider pushes with their foot to propel the bicycle. It provides the connection between the cyclist's foot or shoe
Cycling shoe
Cycling shoes are shoes purpose-built for cycling. There are a variety of designs depending on the type and intensity of the cycling for which they are intended. Key features include rigidity, for more-efficient transfer of power from the cyclist to the pedals, weight, a method of attaching the...

 and the crank
Crankset
The crankset or chainset , is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain, which in turn drives the rear wheel...

 allowing the leg to turn the bottom bracket
Bottom bracket
The bottom bracket on a bicycle connects the crankset to the bicycle and allows the crankset to rotate freely. It contains a spindle that the crankset attaches to, and the bearings that allow the spindle and cranks to rotate. The chainrings and pedals attach to the cranks...

 spindle and propel the bicycle's wheels. Pedals usually consist of a spindle
Axle
An axle 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 its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...

 that threads into the end of the crank and a body, on which the foot rests or is attached, that is free to rotate on bearings
Bearing (mechanical)
A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...

 with respect to the spindle.

Pedals were initially attached to cranks connecting directly to the driven (usually front) wheel.
Encyclopedia
A bicycle pedal is the part of a bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....

 that the rider pushes with their foot to propel the bicycle. It provides the connection between the cyclist's foot or shoe
Cycling shoe
Cycling shoes are shoes purpose-built for cycling. There are a variety of designs depending on the type and intensity of the cycling for which they are intended. Key features include rigidity, for more-efficient transfer of power from the cyclist to the pedals, weight, a method of attaching the...

 and the crank
Crankset
The crankset or chainset , is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain, which in turn drives the rear wheel...

 allowing the leg to turn the bottom bracket
Bottom bracket
The bottom bracket on a bicycle connects the crankset to the bicycle and allows the crankset to rotate freely. It contains a spindle that the crankset attaches to, and the bearings that allow the spindle and cranks to rotate. The chainrings and pedals attach to the cranks...

 spindle and propel the bicycle's wheels. Pedals usually consist of a spindle
Axle
An axle 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 its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...

 that threads into the end of the crank and a body, on which the foot rests or is attached, that is free to rotate on bearings
Bearing (mechanical)
A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...

 with respect to the spindle.

Pedals were initially attached to cranks connecting directly to the driven (usually front) wheel. The safety bicycle
Safety bicycle
A safety bicycle is a type of bicycle that became very popular beginning in the late 1880s as an alternative to the penny-farthing or ordinary and is now the most common type of bicycle. Early bicycles of this style were known as safety bicycles because they were noted for, and marketed as, being...

, as it is known today, came into being when the pedals were attached to a crank driving a sprocket
Sprocket
A sprocket or sprocket-wheel is a profiled wheel with teeth, cogs, or even sprockets that mesh with a chain, track or other perforated or indented material. The name 'sprocket' applies generally to any wheel upon which are radial projections that engage a chain passing over it...

 that transmitted power to the driven wheel by means of a roller chain
Roller chain
Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire and tube drawing machines, printing presses, cars, motorcycles, and simple machines like...

.

Types

Just as bicycles come in many varieties, there are different types of pedals to support different types of cycling.

Flat and platform

Traditionally, platform pedals were pedals with a relatively large flat area for the foot to rest on, in contrast to the quill pedal which had very little surface area.

One form of the platform pedal had a large flat top area and flat bottom for use with toe clips and toe straps. They were designed for greater comfort when using shoes with less than rigid soles. They typically had a smaller cutaway underside giving greater cornering clearance, which was often needed on the track. They were often marketed as being more aerodynamic than conventional quill pedals.

Attaching the shoes to the pedals can increase power on the downstroke and harness additional power on the upstroke. This can be done with toe clips and straps, or with shoes having a cleat; which easily attaches and detaches to a compatibly designed (clipless) pedal. Both methods are common on road bikes, but neither on utility bikes.

In mountain biking
Mountain biking
Mountain biking is a sport which consists of riding bicycles off-road, often over rough terrain, using specially adapted mountain bikes. Mountain bikes share similarities with other bikes, but incorporate features designed to enhance durability and performance in rough terrain.Mountain biking can...

 (MTB) and BMX
BMX
Bicycle motocross or BMX refers to the sport in which the main goal is extreme racing on bicycles in motocross style on tracks with inline start and expressive obstacles, and it is also the term that refers to the bicycle itself that is designed for dirt and motocross cycling.- History :BMX started...

, platform pedals typically refer to any flat pedal without a cage. MTB and BMX riders prefer platforms to cage pedals because they offer more grip using short metal studs, are rounder and do less damage to a rider's shins and ankles during an accident. Cage pedals often scrape skin and flesh off the shin if the rider stops short and loses footing of the pedal.

Platform pedals are available in a wide variety of types and prices, ranging from disposable plastic units used for test rides on new bicycles to high-end downhill models. Budget models may be made of steel or aluminum and incorporate reflectors for safer riding on streets at night. Less expensive platform pedals are generally considered disposable and cannot be rebuilt when worn out.

More expensive platform pedals for the mountain bike market are available with replaceable metal traction pins and cartridge bearings. Lightweight pedals intended for Freeride
Freeride
Freeride is a discipline of mountain biking closely related to downhill cycling and dirt jumping focused on tricks, style, and technical trail features. It is now recognized as one of the most popular disciplines within mountain biking....

 and downhill cycling
Downhill cycling
Downhill biking is a gravity-assisted time trial mountain biking event. Riders race against the clock, usually starting at intervals of 30 seconds , on courses which typically take two to five minutes to complete. Riders come from all around the world. Riders are timed with equipment similar to...

 have been made from exotic metals such as magnesium.

Toe clips typically are not installed on this type of pedal because they are considered unsafe by some MTB and BMX riders. However, fixed gear riders have started using fabric straps instead.

Quill

The quill pedal is a common pedal system on bicycles. It consists of a main axle section that is attached to the bicycle crank arm and contains extensions from the axle to which parallel cage plates are attached at the front and rear of the pedal. In order to utilize the quill pedal, the cyclist pushes his foot against the platform formed by the parallel cage plates.

To improve the performance of the quill pedal toe clips were added. The toe clip is a thin metal or plastic attachment to the front cage of the pedal. The toe clip is shaped like the toe of a shoe and its function is to prevent a cyclist's shoe from slipping off the pedal during the forward pedaling motion. The clip is generally made of metal or high impact plastic. A further enhancement of the quill pedal was modifying the toe clip to allow a strap and buckle to go around or through both the pedal and the toe clip to encircle the cyclist's foot on the top of the pedal. This strap is generally made of leather
Leather
Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...

 or nylon
Nylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...

.

To further improve the quill pedal's efficiency a "cleat" was developed. This cleat consists of a small metal or plastic attachment to the cyclist's shoe. The cleat is slotted and is adapted to engage a quill section of the bicycle pedal. The use of the slotted cleat enhances a cyclist's ability over that provided by toe clips and strap, enabling for greater pedaling efficiency. Although quill pedals can be used with smoothed-soled cycling shoes or ordinary shoes, they were designed to be used with cycling shoes which had a slotted shoeplate attached to its sole. The disadvantage with this system is that to remove the shoe from the pedal a rider had to reach down and loosen the strap by hand or leave the toe strap loose and thus give up some efficiency. This type of pedal and pedal setup was common for racing cyclists until the mid to late 1980s.

Quill pedals are sometimes said to be named for the quill or "pick up tab" on the rear of the pedal. The weight of the toe clip and strap would make the pedal hang upside down, and the rider would tap the quill with their shoe to flip the pedal over so the shoe could be inserted into the pedal.
The main difference between track, road, and touring quill pedals is width. Track pedals are narrow and the front and back plates of the cage are separate, road being a little wider with a one piece cage in a shape of a sideways "U", and touring being the widest to allow for comfort when used with wider, non-racing shoes during longer rides.
While quill pedals can be used for mountain biking, the use of clips here is dangerous as they do not grip well. Cage pedals built for mountain biking are typically serrated so that even when muddied, the pedals can be gripped well by any flat shoe.

Clipless pedals

Clipless pedals (also clip-in or step-in) require a special cycling shoe
Cycling shoe
Cycling shoes are shoes purpose-built for cycling. There are a variety of designs depending on the type and intensity of the cycling for which they are intended. Key features include rigidity, for more-efficient transfer of power from the cyclist to the pedals, weight, a method of attaching the...

 with a cleat fitted to the sole, which locks into a mechanism in the pedal and thus holds the shoe firmly to the pedal. Most clipless pedals lock onto the cleat when stepped on firmly and unlock when the heel is twisted outward, although in some cases the locking mechanism is built into the cleat instead of the pedal. Clipless refers to the toe clip (cage) having been replaced by a locking mechanism and not to platform pedals which would normally not have toe clips.
The clipless pedal was invented by Charles Hanson in 1895. It allowed the rider to twist the shoe to lock and unlock and had rotational float (the freedom to rotate the shoe slightly to prevent joint strain).
The M71 was a clipless pedal designed by Cino Cinelli
Cinelli
Cinelli is an Italian bicycle manufacturing company based in Milan, Italy, producing mostly road bicycles and components; production is estimated at 80 percent components, 20 percent bicycles.- History :...

 and produced by his company in 1971. It used a plastic shoe cleat which slid into grooves in the pedal and locked in place with a small lever located on the back side of the pedal body. To release the shoe a rider had to reach down and operate the lever, similar to the way a racing cyclist had to reach down and loosen the toestrap. The lever was placed on the outside edge of the pedal so that in the event of a fall the lever hitting the ground would release the foot. The pedal was designed for racing, in particular track racing, and because of the need to reach them to unclip they have been referred to as "death cleats".
In 1984, the French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 company LOOK applied downhill snow skiing binding
Ski binding
A ski binding is an attachment which anchors a ski boot to the ski. There are different types of bindings for different types of skiing.-Universal designs:...

 or cleat technology to pedals producing the first widely used clipless pedals. Initially used by triathletes in order to facilitate faster "transitions", Bernard Hinault
Bernard Hinault
Bernard Hinault is a former French cyclist known for five victories in the Tour de France. He is one of only five cyclists to have won all three Grand Tours, and the only cyclist to have won each more than once. He won the Tour de France in 1978, 1979, 1981, 1982 and 1985...

's victory in Tour de France
Tour de France
The Tour de France is an annual bicycle race held in France and nearby countries. First staged in 1903, the race covers more than and lasts three weeks. As the best known and most prestigious of cycling's three "Grand Tours", the Tour de France attracts riders and teams from around the world. The...

 in 1985 then helped secure the acceptance of quick-release clipless pedal systems by cyclists. Those pedals, and compatible models by other manufacturers, remain in widespread use today. The cleat is engaged by simply pushing down and forward on the pedal, or, with some designs, by twisting the cleat in sideways. Then, instead of loosening a toestrap or pulling a lever, the cyclist releases a foot from the pedal by twisting the heel outward.
The next major development in clipless pedals was Shimano's SPD (Shimano Pedaling Dynamics
Shimano Pedaling Dynamics
Shimano Pedaling Dynamics, also known as SPD system is a design of clipless bicycle pedals. The SPD pedal was released by Shimano in 1990. While not the first, its innovation was its small cleat which fitted in a recess in the sole of a shoe designed for SPD use...

) pedal system. Whereas Look cleats are large and protrude from the sole of the shoe, SPD cleats are small and could be fitted in a recess in the sole, making it possible for walking (although comfort will vary, as the soles of different cycling shoes vary in their rigidity depending on design).
Cycling shoes have rigid soles to maximize power transfer and efficiency. They may be specific to road or mountain biking, or usable for both. Shoes designed for mountain biking typically have recessed cleats that do not protrude beyond the sole of the shoe, and have treads for walking on trails, as walking or carrying the bike is often required. Road cycling shoes are typically lighter than their mountain bike counterparts, and feature a protruding cleat and less weather proofing. The protruding cleat makes these shoes impractical for walking, as doing so can damage the cleat.
Mountain bike cleats can generally be mounted without difficulty to road shoes although sometimes an adapter is required. Such attachment is not usually possible for road pedals, as the cleats are normally too large to be mounted on mountain shoes. The smaller mountain bike cleats are attached to the sole of the shoe by two bolts; larger road-specific cleats are attached by three.
Various manufacturers have produced their own designs of clipless pedal systems over the years, most notably BeBop, Campagnolo
Campagnolo
Campagnolo is an Italian manufacturer of high-end bicycle components with headquarters in Vicenza, Italy. The components are organised as groupsets and are a near-complete collection of a bicycle's mechanical parts. Campagnolo's flagship components are the Super Record, Record, and Chorus...

, Coombe
Coombe Clipless Pedal
The Coombe Clipless Pedal was a short production clipless bicycle pedal that saw a small following in the cycling community in the late 1990s and early to mid 2000's.The design is as stated:...

, Crank Brothers, LOOK, Shimano
Shimano
Shimano, Inc. is a Japanese multinational manufacturer of cycling components, fishing tackle, and rowing equipment.In 2005, the company had net sales of US $1.4 billion. Bicycle components provided 75% of its sales income...

, Speedplay
Speedplay (bicycle pedal)
Speedplay is a brand of clipless bicycle pedal manufactured by Speedplay Inc. in San Diego, California. Models include Zero, Light Action, and X for road cycling, Frog for mountain biking, and Drillium for downhill. Speedplay pedals are used by many top professional racers, such as Cadel Evans,...

, and Time
Time (bicycles)
TIME Sport International is a French manufacturer of bicycles and cycling equipment, including bicycle frames, cycling shoes, clipless bicycle pedals, cranksets, and gloves.-History:...

.

Float and tension

"Float" is defined as the degree of movement offered by the cleat within the pedal before release begins. This can be highly important to prevent damage to knees, as most peoples' legs do not remain in a single plane as they pedal. Many standard road pedal systems offer with a 6 degree float cleat. SPD-SL, Look Delta, Look Kéo, and Time cleats are also available in 3 degree and 0 degree float. Road pedal systems commonly colour-code cleats by the amount of float offered (red, black, etc.). Some pedal systems have a fixed non-adjustable float, such as 6 degrees for Crank Brothers and 4.5 degrees for the Kéo Easy. Most cleats develop more float as they wear.

Magnet pedals

Magnetic pedals were introduced as early as 1897, and the Exus Mag Flux Road was available in 1996. More recently, Norbert Sadler and Wolfgang Duerr filed for a patent in 2005. Their pedal uses neodymium iron boron (NdFeB) magnets
Neodymium magnet
A neodymium magnet , the most widely-used type of rare-earth magnet, is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. Developed in 1982 by General Motors and Sumitomo Special Metals, neodymium magnets are the strongest...

. The magnetic pedal system allows for a free choice of foot position, which can also be changed while riding and therefore rests the joints and obviates knee problems. The magnetic pedal system allows for immediate release in all directions. A slight movement of the knee outward or tilting the shoe sole off the pedal results in an easy release. In critical situations a fitful pull will also result in the immediate release. Falls will cause an automatic release from the pedal.

Folding

To maximize compactness, folding bicycle
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 and workplaces or onto public transportation or more easily stored in compact living quarters or aboard a car, boat or plane...

s often have pedals that fold as well.

Attachment

The pedal spindle is threaded
Screw thread
A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread...

 to match a threaded hole at the outboard end of the cranks. Multi-piece cranks have a 9/16 in hole with 20 TPI (a diameter
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

/pitch
Lead (engineering)
Lead is the axial advance of a helix or screw during one complete turn The lead for a screw thread is the axial travel for a single revolution....

 combination fairly unique to this application). One-piece cranks use a 1/2 in by 20 TPI hole. French pedal spindles use M14 x 1.25 (14 mm (0.551181102362205 in) metric diameter with 1.25 mm or 0.0492125984251969 in pitch) threads, and thread loosely into a 9/16 pedal hole. The threading size is often stamped into the crank, near the pedal hole.
The right-side (usually the drive-side) pedal spindle is right-hand threaded, and the left-side (usually the non-drive-side) pedal spindle is left-hand (reverse) threaded to help prevent it from becoming loose by an effect called precession
Precession (mechanical)
Precession is the process of a round part in a round hole rotating with respect to that hole because of clearance between them and a radial force on the part that changes direction. The direction of rotation of the inner part is opposite to the direction of rotation of the radial force. Fretting...

.
Although the left pedal turns clockwise on its bearing relative to the crank (and so would seem to tighten a right-hand thread), the force from the rider's foot presses the spindle against the crank thread at a point which rolls around clockwise with respect to the crank, thus slowly pulling the outside of the pedal spindle anticlockwise (counterclockwise) because of friction and thus would loosen a right-hand thread.
For a short time in the early 1980s, Shimano
Shimano
Shimano, Inc. is a Japanese multinational manufacturer of cycling components, fishing tackle, and rowing equipment.In 2005, the company had net sales of US $1.4 billion. Bicycle components provided 75% of its sales income...

 made pedals and matching cranks that had a 1 inches (25.4 mm) by 24 TPI interface. This was to allow a larger single bearing, as these pedals were designed to work with just one bearing on the crank side rather than the conventional design of one smaller bearing on each side.

See also

  • Crankset
    Crankset
    The crankset or chainset , is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain, which in turn drives the rear wheel...

  • Cycling shoe
    Cycling shoe
    Cycling shoes are shoes purpose-built for cycling. There are a variety of designs depending on the type and intensity of the cycling for which they are intended. Key features include rigidity, for more-efficient transfer of power from the cyclist to the pedals, weight, a method of attaching the...

  • Treadle
    Treadle
    A treadle [from OE tredan = to tread] is a part of a machine which is operated by the foot to produce reciprocating or rotary motion in a machine such as a weaving loom or grinder...

  • Animation of a bicycle pedal
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK