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.
Obsolete chain designs previously used on bicycles included the block chain, the skip-link chain, and the Simpson lever chain. The first chains were of a simple, bushing-less design. These had inherent reliability problems and a bit more friction (and mechanical efficiency losses) than modern chains. With these limitations in mind, the Nevoigt brothers, of the German Diamant Bicycle Company, designed the roller chain in 1898, [1] which uses bushings. More recently, the "bushingless roller chain" design has superseded the bushed chain. This design incorporates the bearing surface of the bushing into the inner side plate, with each plate creating half of the bushing. This reduces the number of parts needed to assemble the chain and reduces cost. The chain is also more flexible sideways, which is needed for modern derailleur gearing, because the chainline is not always straight in all gear selections. [2]
The first solid bush-roller patent was filed by the Renold Chain company in 1880.
Early examples of chain-driven bicycles include the 1869 Guillemot and Meyer, [3] the 1879 Lawson, the 1884 McCammon, [4] the 1884 Starley Rover, and the 1895 Diamant. [1]
Before the safety bicycle, bicycles did not have chains and the pedals were typically attached directly to the drive-wheel, thus limiting top speed by the diameter of the wheel and resulting in designs with front wheels as large as possible. Various linkage mechanisms were invented to raise the effective gear ratio, but with limited success. Using chain drive allowed the mechanical advantage between the drive and driven sprockets to determine the maximum speed, thereby enabling manufacturers to reduce the size of the driving wheel for safety. It also allowed for the development of variable gearing, allowing cyclists to adjust their gearing on the fly, to terrain or road inclination and their strength, obtaining an efficient and workable cadence at various speeds.
A bicycle chain can be very energy efficient: one study reported efficiencies as high as 98.6%. [5] The study, performed in a clean laboratory environment, found that efficiency was not greatly affected by the state of lubrication. [5] A larger sprocket will give a more efficient drive because it moves the point of pressure farther away from the axle, placing less stress on the bearings, thus reducing friction in the inner wheel. Higher chain tension was found to be more efficient: "This is actually not in the direction you'd expect, based simply on friction". [5]
How best to lubricate a bicycle chain is a commonly debated question among cyclists. [6] Liquid lubricants penetrate to the inside of the links and are not easily displaced, but quickly attract dirt. "Dry" lubricants, often containing wax or Teflon, are transported by an evaporating solvent, and stay cleaner in use. The cardinal rule for long chain life is never to lubricate a dirty chain, as this washes abrasive particles into the rollers. [7] Chains should be cleaned before lubrication. The chain should be wiped dry after the lubricant has had enough time to penetrate the links. An alternative approach is to change the (relatively cheap) chain very frequently; then proper care is less important. Some utility bicycles have fully enclosing chain guards, which virtually eliminate chain wear and maintenance. On recumbent bicycles the chain is often run through tubes to prevent it from picking up dirt, and to keep the cyclist's leg free from oil and dirt.
On most upright bicycles, the chain loops through the right rear triangle made by the right chain stay and seat tube. Thus a chain must be separated, (or "broken" ) unless the triangle can be split (usually the seat stay). Chain can either be broken with a chain tool or at a master link. A master link, also known as a connecting link, allows the chain to be inserted or removed with simpler tools, or even no tools, for cleaning or replacement. [6]
Some newer chain designs, such as Shimano and Campagnolo 10-speed chains, require a special replacement pin to be used when installing or reinstalling a separated chain. An alternative to this process is to install a master link, such as a SRAM Power Link or a Wippermann Connex. [8]
Chain wear, often misleadingly called chain stretch, becomes an issue with extensive cycling. The wear is removal of material from the bushings and pins (or half-bushings, in the Sedis design, also, called "bushing-less", where the bushing is part of the inner plate) rather than elongation of the sideplates. [9] The tension created by pedaling is insufficient to cause the latter. Because the spacing from link to link on a worn chain is longer than the 1⁄2 inch (12.7 mm) specification, those links will not precisely fit the spaces between teeth on the sprockets, resulting in increased wear on the sprockets and possibly chain skip on derailleur drive trains, in which pedaling tension causes the chain to slide up over the tops of the sprocket teeth and skip to the next alignment, that reduces power transfer and makes pedaling uncomfortable.
Since chain wear is strongly aggravated by dirt getting into the links, the lifetime of a chain depends mostly on how well it is cleaned and lubricated, and does not depend on the mechanical load. [7] Depending on use and cleaning, a chain can last only 1,000 kilometres (600 miles) (e.g. in cross-country use, or all-weather use), 3,000 to 5,000 km (2,000 to 3,000 mi) for well-maintained derailleur chains, or more than 6,000 kilometres (4,000 mi) for perfectly groomed high-quality chains, single-gear, or hub-gear chains with a full cover chain guard. [10] [11]
Nickel-plated chain also confers a measure of self-lubrication to its moving parts as nickel is a relatively non-galling metal.[ dubious ]
Chain wear rates are highly variable. One way to measure wear is with a ruler or machinist's rule. [12] Another is with a chain wear tool, which typically has a "tooth" of about the same size found on a sprocket. They are placed on a chain under light load, and if the tooth drops in all the way, the chain should be replaced.
Twenty half-links in a new chain measure 10 inches (254 mm), and replacement is recommended before the old chain measures 10+1⁄16 inches (256 mm) (0.7% wear). [6] A more conservative limit is when 24 half-links in the old chain measure 12+1⁄16 inches (306 mm) (0.5% wear). If the chain has worn beyond this limit, the rear sprockets are also likely to wear, in extreme cases followed by the front chainrings. In this case, the 'skipping' mentioned above is liable to continue even after the chain is replaced, as the teeth of the sprockets will have become unevenly worn (in extreme cases, hook-shaped). Replacing worn sprocket cassettes and chainrings after missing the chain replacement window is much more expensive than simply replacing a worn chain.
The chain in use on modern bicycles has a 1⁄2 inch (12.7 mm) pitch, which is the distance from one pin center to another, ANSI standard #40, where the 4 in "#40" indicates the pitch of the chain in eighths of an inch; and ISO standard 606 (metric) #8, where the 8 indicates the pitch in sixteenths of an inch. Its roller diameter is 5⁄16 inch (7.9 mm).
1976: Shimano briefly made their own 10 pitch Dura-Ace track-specific system with 10 mm (3⁄8 in) (approximately) pitch from about 1976 [13] to 1980 [14] —called Shimano Dura-Ace 10 pitch. The Shimano 10 pitch system is incompatible with ANSI standard #40 (1/2″) e.g. chains, sprockets and so on, [15] [16] and was outlawed by the Japan Keirin Association, helping in its demise. [13]
Chains come in 3⁄32 in (2.4 mm), 1⁄8 in (3.2 mm), 5⁄32 in (4.0 mm), or 3⁄16 in (4.8 mm) roller widths, the internal width between the inner plates.
With derailleur-equipped bicycles, the external width of the chain (measured at the connecting rivet) also matters, because chains must not be too wide for the cogset or the chain will rub on the next larger sprocket, and chains must not be too narrow, which allows them to fall between two sprockets.
Chains can also be identified by the number of rear sprockets they can support, anywhere from 3 to 13. The following list enables measuring a chain of unknown origin to determine its suitability.
The Wikibook, "Bicycle Maintenance and Repair", has more details on this topic.
New chains usually come in a stock length, long enough for most upright bike applications. The appropriate number of links must be removed before installation in order for the drive train to function properly. The pin connecting links can be pushed out with a chain tool to shorten, and additional links may be added to lengthen. [19]
In the case of derailleur gears the chain is usually long enough so that it can be shifted onto the largest front chain ring and the largest rear sprocket without jamming, and not so long that, when shifted onto the smallest front chain ring and the smallest rear sprocket, the rear derailleur cannot take up all the slack. Meeting both these requirements is only possible if the rear derailleur is compatible with the gear range being used on the bike. It is broadly accepted as inadvisable to actually use the large/large and small/small gear combinations, a practice known as cross-chaining, due to chain stress and wear. [20]
In the case of single-speed bicycles and hub gears, the chain length must match the distance between crank and rear hub and the sizes of the front chain ring and rear sprocket. These bikes usually have some mechanism for small adjustments such as horizontal dropouts, track ends, or an eccentric mechanism in the rear hub or the bottom bracket. In extreme cases, a chain half-link may be necessary.
In order to reduce weight, chains have been manufactured with hollow pins and with cut-outs in the links. [21] Chains have also been made of stainless steel for corrosion resistance [22] and titanium for weight reduction, but they are expensive. [23] A recent trend is chains of various colors, and at least one manufacturer offers a chain model specifically for electric bicycles. [24]
Notable bicycle chain manufacturers include:
A mountain bike (MTB) or mountain bicycle is a bicycle designed for off-road cycling. Mountain bikes share some similarities with other bicycles, but incorporate features designed to enhance durability and performance in rough terrain, which makes them heavier, more complex and less efficient on smooth surfaces. These typically include a suspension fork, large knobby tires, more durable wheels, more powerful brakes, straight, extra wide handlebars to improve balance and comfort over rough terrain, and wide-ratio gearing optimised for topography and application. Rear suspension is ubiquitous in heavier-duty bikes and now common even in lighter bikes. Dropper posts can be installed to allow the rider to quickly adjust the seat height.
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.
Shimano, Inc., originally Shimano Iron Works (島野鐵工所) and later Shimano Industries, Inc. (島野工業株式会社), is a Japanese multinational manufacturing company for cycling components, fishing tackle and rowing equipment, who also produced golf supplies until 2005 and snowboarding gear until 2008. Named after founder Shozaburo Shimano and headquartered in Sakai, Osaka Prefecture, the company has 32 consolidated and 11 unconsolidated subsidiaries, with the primary manufacturing plants based in Kunshan (China), Malaysia and Singapore.
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 groupset or gruppo is a bicycle component manufacturer's organized collection of mechanical parts. It generally refers to all of the components that make up a bicycle excluding the bicycle frame, fork, stem, wheels, tires, and rider contact points, such as the saddle and handlebars.
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 bicycles. It consists of a series of short cylindrical rollers held together by side links. It is driven by a toothed wheel called a sprocket. It is a simple, reliable, and efficient means of power transmission.
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 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 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.
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.
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.
An electronic gear-shifting system is a method of changing gears on a bicycle, which enables riders to shift with electronic switches instead of using conventional control levers and mechanical cables. The switches are connected by wire or wirelessly to a battery pack and to a small electric motor that drives the derailleur, switching the chain from cog to cog. An electronic system can switch gears faster and, because the system does not use Bowden cables and can calibrate itself, it may require less maintenance.
A master link or quick-release link is a roller chain accessory that allows convenient connection and disconnection of a chain without the need for a chain tool. It acts as a set of the chain's outer plates, so joining two sets of the chain's inner plate ends. Such master links may or may not be re-usable. A chain tool is nonetheless needed to adjust a chain's length, for example to shorten a new chain before connecting its ends. They are used on bicycles and motorcycles.
Wippermann jr GmbH is a roller chain manufacturer located in Hagen, Germany, and founded by Wilhelm Wippermann in 1893. They make the Connex brand of bicycle chains and master links. Their bicycle chains include such high-end features as nickel-plating, hollow pins, stainless steel, titanium rollers, and cutout plates. In 2008, Wippermann published wear test results in which their bicycle chains performed well. Wippermann chains are used by professional cyclists in the Tour de France.
KMC Chain Industrial Co., Ltd. is a roller chain manufacturer headquartered in Taiwan, R.O.C. with corporate entities in the US, Continental Chain Company, and Europe, KMC Chain Europe BV. They make cam driving chains, balance driving chains, oil pump chains, motorcycle chains, and industrial chains. They manufacture and market bicycle chains and master links under their own KMC brand and supply them to others, including Shimano. KMC chains are used in the Tour de France by riders such as Gustav Larsson, Swedish time trial champion. KMC was founded by Charles Wu in 1977, and was the largest bicycle chain manufacturer in the world in 2011.
KMC have achieved this with the pared down profile and slotted plates (something Campag also do with the Ultra 10-speed chain) and hollow pins connecting everything together.
Wippermann claims that its Black Edition stainless-steel ConneX chain is the toughest, most corrosion-resistant derailleur chain on the market.
Titanium chain from YBN ... at US$180 (approx £110) you're unlikely to see too many of these around.
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