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.
The history of bicycle drivetrain systems is closely linked to the history of the bicycle. Major changes in bicycle form have often been initiated or accompanied by advances in drivetrain systems. Several early drivetrains used straight-cut gears that meshed directly with each other outside of the hub. [1] [2] Some bicycles have used a double-sided rear wheel, with different-sized sprockets on each side. To change gears, the rider would stop and dismount, remove the rear wheel and reinstall it in the reverse direction. Derailleur systems were first developed in the late 19th century, but the modern cable-operated parallelogram derailleur was invented in the 1950s.
Bicycle drivetrain systems have been developed to collect power from riders by a variety of methods.
Bicycle drivetrain systems have been developed to transmit power from riders to drive wheels by a variety of methods. Most bicycle drivetrain systems incorporate a freewheel to allow coasting, but direct-drive and fixed-gear systems do not. The latter are sometimes also described as bicycle brake systems.
Some human powered vehicles, both historical and modern, employ direct-drive. Examples include most Penny-farthings, unicycles, and children's tricycles.
Another interpretation of direct-drive is that the rider pushes directly against the ground with a foot, as employed in balance bicycles, kick scooters, and chukudus.
In 1991, a two-wheel drive bicycle was marketed under the Legacy name. It used a flexible shaft and two bevel gears to transmit torque from the rear wheel, driven by a conventional bicycle chain with derailleurs, to the front wheel. [11] In 1994, Steve Christini and Mike Dunn introduced a two-wheel drive option. [12] Their AWD system, aimed at mountain bikers, comprises an adapted differential that sends power to the front wheel once the rear begins to slip. In the late 1990s, 2WD 'Dual Power' mountain bikes were sold in Germany under the Subaru name. They used one belt to transfer power from the rear wheel to the head tube, a small gearbox to allow rotation of the front fork, and then a second belt to transfer power to the front wheel. [13]
A cyclist's legs produce power optimally within a narrow pedalling speed range. Gearing is optimized to use this narrow range as best as possible. Bicycle drivetrain systems have been developed to convert speed and torque by a variety of methods.
Several technologies have been developed to alter gear ratios. They can be used individually, as an external derailleur or an internal hub gear, or in combinations such as the SRAM Dual Drive, which uses a standard 8 or 9-speed cassette mounted on a three-speed internally geared hub, offering a similar gear range as a bicycle with a cassette and triple chainrings.
While several combinations of power collection, transmission, and conversion exist, not all combinations are feasible. For example, a shaft-drive is usually accompanied by a hub gear, and derailleurs are usually implemented with chain drive.
A tandem bicycle or twin is a 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. Recumbents are available in a wide range of configurations, including: long to short wheelbase; large, small, or a mix of wheel sizes; overseat, underseat, or no-hands steering; and rear wheel or front wheel drive. A variant with three wheels is a recumbent tricycle.
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.
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.
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.
SRAM LLC is a privately owned bicycle component manufacturer based in Chicago, Illinois, United States, founded in 1987. SRAM is an acronym comprising the names of its founders. The company produces a range of cycling components, including Grip Shift, and separate gravel, road, and mountain drivetrains from 7 to 12 speed. SRAM developed the Eagle line of mountain bike specific drivetrain components intended to improve shifting performance. SRAM was also the first to release a dedicated "one by" drivetrain with a single front chainring for road bikes.
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.
SR Suntour is a Taiwanese manufacturer of bicycle components, formed in 1988 when Osaka based SunTour (Maeda) went bankrupt and was purchased by Sakae Ringyo Company, a major Japanese maker of aluminum parts, particularly cranks and seat posts. SunTour's sales and commercial success peaked from the late 1970s to the mid-1980s.
A front freewheel or freewheel crank is a freewheel mechanism used on some bicycles which enables the drivetrain of the bicycle to continue spinning while the rider rolls, but stops pedaling, or coasts. Unlike regular bicycles, a front freewheel can make it possible to shift gears using a derailleur while the rider is coasting if paired with a fixed rear hub or a freehub with a slight resistance in the freewheel mechanism, which causes the chain to continue spinning with the wheel rotation.
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 rowbike is an example of a rowing cycle, hybrid fitness/transport machine that combines a bicycle, and a rowing machine. "Rowbike" is a trademark of the Rowbike company. The Rowbike was invented by Scott Olson, the creator of Rollerblade inline skates. "Rowling" is a combination of rowing and rolling, and is sometimes used in place of rowing when describing a Rowbike.
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.
Flip-flop hubs, also called double-sided hubs, are rear bicycle hubs that are threaded to accept fixed cogs and/or freewheels on both sides.
A rowing cycle is a wheeled vehicle propelled by a rowing motion of the body. Steering, braking, and shifting are usually done by the handlebars. Feet are on symmetrical foot rests, as opposed to rotating pedals. Unlike many rowing boats, the rider faces forward. Rowing cycles exist in numerous designs, particularly with respect to frames and drive mechanisms. Commercial production numbers for rowing cycles are small compared to that of standard bicycles.
A gearbox bicycle is a bicycle that uses a gearbox to convert torque and rotational speed from the power source, usually the rider's legs, to what is desired at the drive wheel. The gearbox is usually incorporated into the frame near the crank, and it may be used in addition to or instead of derailleur gears or a hub gear. Cited advantages include improved shifting performance, protecting the gearing from damage and exposure to dirt and moisture, as with hub gears, plus locating the additional mass between the two wheels and on the frame where it may be suspended, unlike with hub gears.
Here we have not one but TWO examples of bikes that raise and lower the rider during each pedal stroke. On both of these bikes, the rider pedals with his feet together and stands up and sits back down to propel himself.
Slide the handles in and out as you ride, with the motion transmitted to the front wheel via a system of cords and springs.
There is no mechanical connection between the cranks and rear wheel at all. Instead, the cranks are connected to an alternator, which continually recharges the battery that powers the 250-watt motor at the rear wheel.
| Frame |  | |
|---|---|---|
| Wheels | ||
| Drivetrain | ||
| Cabling | ||
| Peripherals | ||