The Q factor or quack factor [1] [2] of a bicycle is the distance between the pedal attachment points on the crank arms, when measured parallel to the bottom bracket axle. [3] It may also be referred to as the "tread" of the crankset.
The Q factor or quack factor [1] [2] of a bicycle is the distance between the pedal attachment points on the crank arms, when measured parallel to the bottom bracket axle. [3] It may also be referred to as the "tread" of the crankset.
The "Q" stands for "quack", a reference to the wide stance and waddling gait of ducks. [4] The term was coined by Grant Petersen during his time at Bridgestone Bicycles. [5]
Q factor is a function of both the bottom bracket width (axle length) and the cranks. Bottom brackets axles vary in length from 102mm to 127mm. Mountain bike cranks are typically about 20mm wider than road cranks. [6]
A larger Q factor (wider tread) will mean less cornering clearance (while pedaling) for the same bottom bracket height and crank length. A smaller Q factor (narrower tread) is desirable on faired recumbent bicycles because then the fairing can also be narrower, hence smaller and lighter. [6] Sheldon Brown said that a narrower tread is ergonomically superior because it more closely matches the nearly-inline track of human footsteps. [7]
Research from the University of Birmingham in the United Kingdom suggests narrower Q factors are more efficient, likely due to improved application of force during the pedal stroke, as well the potential for reduced knee variability and risk of injury. [8] [9]
"Old Faithful" was a homebuilt bike that Graeme Obree famously used in 1993 to 1995 at his attempts at the hour record, which had a very narrow bottom bracket measuring only 40 mm wide, and famously also used "washing machine" bearings. [10]
Walser model 5 designed by Andy Walzer from Switzerland was a narrow time trial bike with a 50 mm bottom bracket [11] notably used by Jan Ullrich in the 2003 Tour de France riding for Team Bianchi, and from 2004 to 2006 for T-Mobile Team. The bike also had a narrow rear hub spacing of 110 mm, [12] which is 20 mm narrower than the 130 mm that was standard on road and time trial bikes at the time, resulting in the bike needing custom cranks and custom rear wheels. Narrow Walzer bikes are also said to have been owned by Michael Rich and Lance Armstrong, [13] but for Armstrong the bicycle allegedly resulted in reduced power output "and the smaller Q-factor was rumoured to have induced tendonitis". [14]
Pinarello Bolide F HR was a track bicycle used by Filippo Ganna in 2022 to set the hour record, and featured a narrow profile with a 54 mm bottom bracket, 89 mm rear hub and 69 mm front hub. [15]
A tandem bicycle or twin is a form of bicycle designed to be ridden by more than one person. The term tandem refers to the seating arrangement, not the number of riders. Patents related to tandem bicycles date from the mid 1880s. Tandems can reach higher speeds than the same riders on single bicycles, and tandem bicycle racing exists. As with bicycles for single riders, there are many variations that have been developed over the years.
A recumbent bicycle is a bicycle that places the rider in a laid-back reclining position. Some recumbent riders may choose this type of design for ergonomic reasons: the rider's weight is distributed comfortably over a larger area, supported by back and buttocks. On a traditional upright bicycle, the body weight rests entirely on a small portion of the sitting bones, the feet, and the hands.
A tricycle, sometimes abbreviated to trike, is a human-powered three-wheeled vehicle.
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 triangle and a paired rear triangle. This is known as the diamond frame. Frames are required to be strong, stiff and light, which they do by combining different materials and shapes.
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 or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainrings or chainwheels attached to the cranks, arms, or crankarms to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain.
A bicycle chain is a roller chain that transfers power from the pedals to the drive-wheel of a bicycle, thus propelling it. Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics.
The pedal is the part of a bicycle that the rider pushes with their foot to propel the vehicle. It provides the connection between the cyclist's foot or shoe and the crank allowing the leg to turn the bottom bracket spindle and propel the bicycle's wheels. A pedal usually consists of a spindle that threads into the end of the crank, and a body on which the foot rest is attached, that is free to rotate on bearings with respect to the spindle.
A touring bicycle is a bicycle designed or modified to handle bicycle touring. To make the bikes sufficiently robust, comfortable and capable of carrying heavy loads, special features may include a long wheelbase, frame materials that favor flexibility over rigidity, heavy duty wheels, and multiple mounting points.
The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals attach to the cranks. Bottom bracket bearings fit inside the bottom bracket shell, which connects the seat tube, down tube and chain stays as part of the bicycle frame.
Cicli Pinarello S.p.A. is an Italian bicycle manufacturer based in Treviso, Italy. Founded in 1953, it supplies mostly handmade bicycles for the road, track, E-bikes(NYTRO), mountain bikes and cyclo-cross. The company also produces an in-house component brand – MOST.
A racing bicycle, also known as a road bike is a bicycle designed for competitive road cycling, a sport governed by and according to the rules of the Union Cycliste Internationale (UCI).
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 narrow and inflated to high pressure to reduce rolling resistance.
A fixed-gear bicycle is a bicycle that has a drivetrain with no freewheel mechanism such that the pedals always will spin together with the rear wheel. The freewheel was developed early in the history of bicycle design but the fixed-gear bicycle remained the standard track racing design. More recently the "fixie" has become a popular alternative among mainly urban cyclists, offering the advantage of simplicity compared with the standard multi-geared bicycle.
On a bicycle, the cassette or cluster is the set of multiple sprockets that attaches to the hub on the rear wheel. A cogset works with a rear derailleur to provide multiple gear ratios to the rider. Cassettes come in two varieties, freewheels or cassettes, of which cassettes are a newer development. Although cassettes and freewheels perform the same function and look almost the same when installed, they have important mechanical differences and are not interchangeable.
A bicycle saddle, often called a bicycle seat, is one of five contact points on an upright bicycle, the others being the two pedals and the two handles on the handlebars. The bicycle saddle has been known as such since the bicycle evolved from the draisine, a forerunner of the bicycle. It performs a similar role as a horse's saddle, not bearing all the weight of the rider as the other contact points also take some of the load.
Bicycle suspension is the system, or systems, used to suspend the rider and bicycle in order to insulate them from the roughness of the terrain. Bicycle suspension is used primarily on mountain bikes, but is also common on hybrid bicycles.
A crank forward bicycle has the bottom bracket and cranks set further forward, relative to the seat, than a traditional upright bicycle. Bicycles of this type are also called easy bikes/EZBs, flat foot bikes, laid back bikes, semi-recumbent/semi-bent bikes and ground-reach bikes.
The following outline is provided as an overview of and topical guide to bicycles: