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The three-speed bicycle is a bicycle that uses internal hub gears at the rear wheel hub to provide three gear ratios.
Three-speed hubs have been in use since the early 1900s. Though they are heavier than comparable derailleur systems, internal-gear hub systems generally last longer and require less maintenance.
Typically, in low gear, the rear sprocket turns faster than the wheel; in middle gear, the rear sprocket turns at the same speed as the wheel; in high gear, the rear wheel turns faster than the sprocket.
During their heyday, three-speed hubs were used in all applications, including racing and time trialling, cargo cycling, utility cycling, and commuting. In many parts of the world, three-speed hubs are still preferred for commuting and other types of utility cycling over derailleur systems.
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A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered or motor-assisted, pedal-driven, single-track vehicle, with two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.
A derailleur is a variable-ratio bicycle gearing system consisting of a chain, multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another.
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 hub gear, in contrast with derailleur gears where the gears and mechanism are exposed to the elements. Changing the gear ratio was traditionally accomplished by a shift lever connected to the hub with a Bowden cable, and twist-grip style shifters have become common.
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.
In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated.
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, relatively slow rides through very flat urban areas. It is a form of utility bicycle commonly seen around the world, built to facilitate everyday short-distance riding in normal clothes in cold-to-mild weather conditions. It is therefore a bicycle designed for very short-range practical transportation, as opposed to those primarily for recreation and competition, such as touring bicycles, road bicycles, and mountain bicycles. Utility bicycles are the most common form globally, and comprise the vast majority found in the developing world. City bikes may be individually owned or operated as part of a public bike sharing scheme.
Sturmey-Archer was a manufacturing company originally from Nottingham, England. It primarily produced bicycle hub gears, brakes and a great many other sundry bicycle components, most prominently during its heyday as a subsidiary of the Raleigh Bicycle Company. In the past, it also manufactured motorcycle hubs, gearboxes and engines.
A single-speed bicycle is a type of bicycle with a single gear ratio. These bicycles are without derailleur gears, hub gearing or other methods for varying the gear ratio of the bicycle.
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.
Gear inches is an imperial measure corresponding to the diameter in inches of the drive wheel of a penny-farthing bicycle with equivalent (direct-drive) gearing. A commonly used metric alternative is known as metres of development or rollout distance, which specifies how many metres a bicycle travels per revolution of the crank.
A shaft-driven bicycle is a bicycle that uses a drive shaft instead of a chain to transmit power from the pedals to the wheel. Shaft drives were introduced in the 1880s, but were mostly supplanted by chain-driven bicycles due to the gear ranges possible with sprockets and derailleurs. Around the 2000s, due to advancements in internal gear technology, a small number of modern shaft-driven bicycles have been introduced.
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 freehub is a type of bicycle hub that incorporates a ratcheting mechanism.
The Rohloff Speedhub is an epicyclic internal hub gear for bicycles, developed and patented by Rohloff AG. It has been manufactured and marketed by that company since 1998. The Speedhub 500/14 has 14 equally spaced, sequential, non-overlapping gear ratios operated by a single twistgrip. The overall gear range is 526%, meaning the highest gear is 5.26 times as high as the lowest gear. Individual gear shifts when shifting up give an increase of about 13.6%.
Bicycle gearing is the aspect of a bicycle drivetrain that determines the relation between the cadence, the rate at which the rider pedals, and the rate at which the drive wheel turns.
A belt-driven bicycle is a chainless bicycle that uses a flexible belt, typically a synchronous toothed design, in order to transmit power from the pedals to the wheel.
Bicycle drivetrain systems are used to transmit power on bicycles, tricycles, quadracycles, unicycles, or other human-powered vehicles from the riders to the drive wheels. Most also include some type of a mechanism to convert speed and torque via gear ratios.
A quick release skewer is a mechanism for attaching a wheel to a bicycle. It consists of a rod threaded on one end and with a lever operated cam assembly on the other. The rod is inserted into the hollow axle 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 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.