Bicycle chain
The bicycle chain is part of the chain drive used on bicycles , with which the torque generated by the pedaling force of the rider is transmitted to the drive wheel . The efficiency of a chain can be up to 98%. In the case of derailleurs , the chain that is shifted transversely and continues to run with little tension changes to a parallel sprocket or chainring. The outer links of the chain are often specially shaped to improve this change.
With a classic bicycle frame, the chain is usually passed through the frame triangle on the right-hand side of the rear end and permanently riveted with a chain rivet (e.g. with Shimano chains) or connected by a detachable chain lock (e.g. with SRAM and KMC chains).
history
- 1878: The first large- scale roller chains with large pitch are introduced at the same time as the safety low wheel. The uneven running due to the large pitch is a disadvantage.
- 1880: The Swiss Hans Renold (* 1852 in Aarau) receives the first English patent for the roller chain. A Renold company produces roller chains.
- 1898: The Nevoigt brothers , owners of the Saxon Diamant Fahrradwerke , invent the double roller chain, which is today's world standard.
- 1895: William Spears Simpson invents the Simpson lever chain , in which the chainring engages on the inner pin and the pinion engages the outer pin of the triangular chain links.
- 1978: The French company Sedisport builds the first serial bearing collar chain . The holes in the inner plates are shaped into bearing collars that replace the sleeve. This improves lubricant flow and lateral mobility. Weight and manufacturing costs are reduced.
- 1982: Shimano introduces the Uniglide chain, with flared outer plates that improve shifting properties.
- 1987: Regina develops a boltless chain in which the sleeves are passed through the outer plates. The weight saving of 65 g comes at the price of increased wear.
- 1988: Rohloff improves flexibility and shift quality by means of inwardly bent outer plates.
Today chains with sleeves are used for hub gears and bearing collar chains for chain gears, almost exclusively with a pitch of 1/2 ".
Dimensions and designs
Special chain gears are available for derailleur gears that improve shifting comfort. The more sprockets there are in the rear sprocket , the narrower the chain should be. The usual dimension marking for a bicycle chain consists of two dimensions in inches (dimension 1 × dimension 2). The first dimension describes the distance from joint to joint (the chain pitch ), which is 1/2 "in most of today's bicycle chains. The second dimension describes the inner width at the narrowest point, i.e. between the inner links.
- 5/8 "× 5/32" for old touring bikes (before 1945)
- 1 "× 1/8" as a block chain
- 1/2 "× 1/8" for hub gears , BMX and track bikes (outer width: 8.6–9.4 mm depending on the manufacturer)
- 1/2 "× 3/32" for modern hub gears (Rohloff Speedhub / Alfine) as well as for derailleur gears with up to 8-fold switchable sprocket sets (outer width: 7.1 mm - 8-fold switchable, 7.3 mm - 7 (- 8) -fold switchable) (suitable for a Shimano InteractiveGlide chainring and sprocket thickness of 2.35 mm)
- 1/2 "× 11/128" for derailleur gears with up to 9-fold switchable sprocket sets (Shimano HyperGlide with outer width 6.8 mm and Campagnolo with outer width 6.6 mm)
- 1/2 "× 10/128" for derailleur gears with up to 10-fold switchable sprocket sets (Shimano-HyperGlide with outer width 6.15 mm and Campagnolo with outer width 5.9 mm)
- 1/2 "× 9/128" for derailleur gears with up to 11-speed gear sets (Campagnolo with an outer width of 5.5 mm)
The weight of a chain varies depending on the application and length. Bicycle chains for derailleur gears weigh around 250 to 350 g, hub gear chains 275–350 g per 100 chain links.
While the manufacturers usually include a robust and reusable chain lock with the chains for bicycles without derailleur gears, modern narrow chains are mostly locked by riveting. Shimano adds a special rivet pin to the narrow chains to close the chain, which has a guide pin to simplify handling, which is broken off after riveting. To extend the shelf life, it is recommended that this pin be pushed in in the same direction in which the previous pin was pushed out (if the chain was previously shortened). In addition, the outer plates should be at the front in the chain running direction before they are riveted. And if the chain is to be opened again later, this should not be done at the point where the special locking pin was used during assembly.
Chain lock
A chain lock replaces the outer plates and bolts of a regular chain link and is used to lock and replace the chain.
Wide chains for use with hub gears are connected with a chain lock with extended bolts. The ends of the bolts are grooved all around so that an elongated locking ring can be pushed over them. The locking ring can be locked and released again with combination pliers .
In the case of derailleur gears, the bolts of the chain lock must not protrude laterally, as otherwise the fit and movement of the chain would be impeded (e.g. in the cage of the rear derailleur ). The additional snap ring on the side is therefore replaced by outer brackets that are provided with an elongated hole that widens slightly towards the center of the outer bracket. The bolts, which are provided with a fine groove, can be inserted there and, when pulled hard, slide into the narrower part of the elongated hole and engage. The chain lock is opened by pushing it together, either by inserting needle-nose pliers between the rollers or by folding the chain in a Z-shape on the chain lock and pressing it together with water pump pliers .
Chain line
In the top view of the bicycle, the chain line is the line the chain appears to be in its imaginary middle position. It runs through the middle sprocket and the middle chainring or, with an even number of sprockets or chainrings, through the middle between two blades or sprockets. The distance between the center of the frame and the chain line is also called the chain line for short. The usual values for this distance are 47.5 mm or 50 mm, with track bikes usually 42 mm.
The chain line determines the angle at which the bicycle chain runs between the front chainrings and the rear sprockets. Ideally, the chainring and sprocket are in a straight line. In this case, the optimal power transmission is possible - the efficiency reaches its maximum, the wear a minimum. The chain line of a derailleur should be chosen so that the chain runs as straight as possible in the most frequently used gears.
As well as the Q factor (the horizontal distance between the outer edges of the left and right crank) the chain line, by the use of an inner bearing shaft to be changed with a different projection of a different length or a crank. Modern cranksets with external bearings are often only available in a few variants. Minor changes can also be made by using washers between the flange of the bearing sleeves and the bottom bracket shell.
Inlet elongation
With new chains, the chain pin and the chain sleeve or bearing collar touch each other in a linear fashion. Over the first 100–200 km there is an increased elongation due to the small contact area between the two parts, while the radii adapt to each other.
wear
During use, there is abrasion between the connecting pin and the sleeves or, in the case of a sleeveless chain, the bearing collar and, as a result, the chain is elongated. If a certain length is exceeded, there will be increased wear on the chainring and sprockets . In order to maximize its service life, the elongation of the chain should be checked regularly with a chain gauge, a steel ruler or a caliper , see chain wear measurement .
The wear and tear and service life of the chain essentially depend on the amount of abrasive mineral particles that penetrate the joints. Chains that run in a closed chain case or that are protected from direct throwing of mud and fine sand by the front and rear wheels last much longer.
If there is thin oil on the chain, the fine dust that settles on the chain can be carried into the joints of the chain together with the oil. If the chain runs rather dry, abrasive particles with thin-bodied mud can get inside the chain in wet weather. New chains are therefore supplied with a tough lubricant that prevents both. If this smear layer has worn out, the protection can be renewed in different ways:
- The chain is immersed in a bath of heated lubricant, which is not very sticky after cooling and hardly binds dust.
- If the lubrication inside the chain has not yet been washed out or has already been renewed, the chain can also be dipped in heated wax.
- Alternatively, solvent-based lubricants or waxes can be applied. Even at room temperature, these are liquid enough to distribute themselves adequately on the chain and then solidify through evaporation of the solvent.
- Special chain oils or adhesive lubricants that are neither heated nor contain solvents usually remain somewhat sticky after application, so that they bind dust to a certain extent. They are usually thick enough not to carry the dust inside the chain, but a black film of lubricant remains on the chain, which stains clothing and skin when touched.
The only sensible way to remove the abrasive particles that got inside the chain is to take the chain off the wheel and rinse it in a bath of solvent or thin oil. Smaller containers for cleaning agents with rotating round brushes are also available, in which the chain can be inserted and pulled through without removing it from the bike. However, the flushing effect is limited.
The illustration on the right compares a new chain with a used one. Normal quality chains elongate by 1 to 2% after about 5000 km. The picture below shows a single split pin. Where it was pressed in the outer link, the diameter is unchanged at 3.7 mm. The wear caused by the movement of the bearing collar of the inner link under tensile load led to an abrasion of about 0.2 mm after about 4000 km. In relation to a chain link ~ 13 mm in length, this corresponds to the elongation observed.
The skewing of the chain, which is unavoidable in chain shifts, and shifting under load increase wear. Since the wear occurs particularly when the chain links move around chainrings and sprockets, the use of large chainrings and large sprockets has a wear-reducing effect. Long chains like those of recumbent bikes last longer because the number of revolutions of the chain is inversely proportional to the chain length for the same mileage of the vehicle; per crank turn the chain is moved further according to the number of teeth on the chainring, but with longer chains the feed is distributed over more chain links so that each individual chain link engages less often. Correspondingly, the short secondary chains of three-wheelers are subject to high wear and tear, as they have a high number of revolutions. However, since they generally run faster than the primary chain, the chain pull is lower, which has a wear-reducing effect; on the other hand, they also circulate more frequently due to the higher speed of rotation.
The mileage varies from 1000 km with use with derailleur gears in bad weather on unpaved roads, over 3000 to 5000 km with derailleur gears with good care or largely dry conditions to over 6000 km with wide chains without derailleur gears and good care. Protected chains, such as in Dutch bikes and velomobiles , can last considerably longer; mileage of up to 100,000 km is reported.
A chain stay protector attached to the chain stay prevents the bicycle chain from hitting the tube of the chain stay when driving over uneven ground.
Chain maintenance
A closed chain case prevents dust and sand from mixing with the chain's lubricating oil and increasing wear and tear on the chain. Regular cleaning of the chain can remove some of the abrasive dust. With an open-running chain with lubrication, however, it cannot ultimately be prevented that fine particles mix with the oil or grease used.
The relatively solid, dry grease, which was applied to all surfaces during the manufacture of the chain, is the best possible lubricant, as it adheres well, is hardly washed off by moisture and does not bind dust. It is therefore advisable not to oil a new chain or to clean it with cleaning agents until the first signs of rust appear, so that the grease applied during manufacture is not diluted with thin oils or removed by cleaning agents. On the other hand, it can make sense to preserve the lubricant of a brand new chain for as long as possible by applying wax from time to time.
Since it is not possible to relubricate the inner workings of a chain with a solid lubricant without disassembling it, a chain with rust must be treated with oil. The oil used should be as thick as possible, since a thin oil washes out the grease that is still inside the chain and at the same time carries dust particles into the inside of the chain.
Oil-free lubricants based on silicone or PTFE (polytetrafluoroethylene; DuPont - trade name : Teflon), which are not sticky, but are quickly rinsed off in rainy weather, which requires relubrication after every trip in the rain, are also suitable. Oil for automatic transmissions can also be used .
Instead of wax and oil, a grease or adhesive oil can be applied, as is often used on motorcycle chains. These pasty and viscous lubricants bind dust particles on the surface of the chain and reliably prevent the original lubricant from being washed out and the chain from rusting. A disadvantage is the black film of lubricant that forms on the chain, which can come into contact with the skin or with clothing if the chains are open. This type of lubrication is therefore particularly recommended when the chain runs in a closed chain case.
The best way to relubricate the inside of a chain without having to accept a permanent lubricating film on the surface afterwards is to use a hot grease or a solvent-based lubricant, which leaves a solid layer of smear after cooling or evaporation of the solvent . The latter are also offered for use on motorcycle chains.
Motor oil for lubricating internal combustion engines should not be used on parts that come into contact with moisture. It contains surfactants, which are supposed to remove residues from the interior of combustion engines, but which lead to rapid rust formation on contact with water. Some household oils contain acid and resin and should also not be used unless it can be ruled out that they will become resinous over time.
Chainrings and sprockets
An elongated chain attacks the teeth of the chainrings and sprockets, which means that they wear out faster than with a new chain. You can choose to change the chain with relatively little elongation in order to protect the chainrings and sprockets, or you can drive the chain as long as possible and change chainrings and sprockets together with the chain.
Clues:
- With a chain elongation of 0.075 mm (based on a chain link), the chain should be changed (typically after approx. 1000–2000 km, depending on the chain type, load and contamination).
- With an elongation of 0.1 mm, the small sprockets in particular show wear (after 2000–4000 km)
- With an elongation of 0.2 mm, clear wear can be seen on the sprockets, as well as on the large chainrings (after 3000–4000 km).
- If the elongation exceeds 0.2 mm, it is probably no longer enough to just change the chain, but also the rear sprockets.
Synchronous chain in tandem
Most tandems are equipped with a second chain, the synchronous chain. This usually runs on the left side and connects the two crank sets with each other. This is an ordinary bicycle chain with an adjusted length.
Secondary chain on a tricycle
Tricycles are often equipped with a differential gear (which was invented for tricycles). There is then no space on the rear axle for gear hubs or derailleur gears. The problem is structurally solved so that in front of the rear axle z. B. a shift hub is arranged, which is driven from the chainring via a normal bicycle chain, the primary chain. On the left side of the hub, another chain sprocket is mounted on the housing, which then drives the differential gear on the rear axle via a second short chain, the secondary chain.
Alternatives
There is a rare alternative to the bicycle chain
literature
- Michael Gressmann, Franz Beck, Rüdiger Bellersheim: specialist knowledge of bicycle technology. 1st edition. Verlag Europa-Lehrmittel, Haan-Gruiten 2006, ISBN 3-8085-2291-7 .
Web links
- the production of bicycle chains in the program with the mouse
- ADFC technical committee for bicycle chain technology
- Olaf Schultz's chain blog - investigations into wear behavior
- Chain maintenance
- Detailed instructions and video for changing the bicycle chain
- the phrase " would have, would have, bicycle chain " on Wiktionary
Individual evidence
- ↑ http://www.diamantrad.com/geschichte/zeitreise/
- ↑ http://www.arnowelzel.de/sheldonbrown/chainline/
- ↑ The Rohloff company used trochoid-shaped bearing collars for their chains , which reduce the initial surface pressure ( patent EP 0396701). Rohloff no longer makes chains.
- ↑ http://www.sheldonbrown.com/brandt/chain-care.html (English)
- ↑ http://www.kmcchain.com/index.php?ln=en&fn=service#4 (English)
- ↑ http://www.sheldonbrown.com/chains.html