Here\u2019s a run-down of everything you need to know about bicycle chains, including the structure of a chain, different \u2018speed\u2019 chains, compatibility, chain length and more. Use the links below to jump to the section you need \u2013 or read on.<\/p>\n
- Chain structure<\/a><\/li>\n
- Chain dimensions<\/a><\/li>\n
- Chain width and \u201cspeeds\u201d<\/a><\/li>\n
- Chain compatibility<\/a><\/li>\n
- Chain length<\/a><\/li>\n
- Chain materials and construction<\/a><\/li>\n
- Frequently asked questions<\/a><\/li>\n<\/ul>
What is the structure of a bicycle chain?<\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>A bike chain is made up of a series of links, comprised primarily of side plates, pins and rollers.<\/span><\/figcaption> Our Media<\/i><\/span><\/div>\n A chain is made up of a series of links. Most chains have alternating wide and narrow links in a pattern that repeats for the length of the chain.<\/span><\/p>\n
Each link has two side plates, which are held together by rivets (also called pins) and a roller sits on the central section of each rivet and engages with the sprockets on the bike\u2019s gears. In some chains, there can be a separate bushing on either side of the roller, although these are usually absent from modern chains.<\/p>\n
To make the chain continuous, a joining pin (sometimes called a \u2018rivet\u2019) can be pushed part-way out of a link using a chain tool then pushed back into the chain around a link from the chain\u2019s other end.<\/p>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>A chain is designed to mesh with the chainrings and cassette on the bike\u2019s drivetrain, to transfer your power through the pedals into forward propulsion.<\/span><\/figcaption> Adam Gault \/ Getty Images<\/i><\/span><\/div>\n Campagnolo\u2019s chains are joined with a bullet-shaped pin that\u2019s longer than the chain is wide; the rounded end of the link pin is broken off (the technical term for this is \u2018peened\u2019) once the pin has been pushed into place in the chain.<\/p>\n
As a side note, not all chain tools have a peening function for Campagnolo chains, so check yours does if you have a groupset from the Italian brand.<\/p>\n
The other method commonly used to close the chain is to use a quick-link. This comes in two halves, which push through the rivet holes in the side plates from opposite sides and mesh with each other. They are either designed to be joined by pulling on either side of the link or to engage with each other at an angle, staying connected once the chain is straightened out.<\/p>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Quick-links are commonly used to close the chain.<\/span><\/figcaption> Oli Woodman \/ Immediate Media<\/i><\/span><\/div>\n Some quick-links can be separated and are reusable, whereas others, such as those used in Shimano\u2019s and SRAM\u2019s higher-spec chains, can\u2019t be separated once put in place, because the quick-link connection isn\u2019t as strong the second time round.<\/p>\n
However, some riders and mechanics reuse quick-links without issue. It\u2019s up to you if you want to take the risk.<\/p>\n
What are the dimensions of a bicycle chain?<\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>The distance between links is known as \u2018pitch\u2019.<\/span><\/figcaption> Getty Images<\/i><\/span><\/div>\n The standard distance between links, or pitch, of a bicycle chain is \u00bdin (12.7mm), although there are occasional experiments with metric pitch (10mm) chains and Team GB was rumoured to be using \u215cin pitch chains on its track bikes at the Tokyo Olympics<\/a>.<\/p>\n
The inner link of a bike chain is narrower than the outer link, with a narrower space between the links. That\u2019s used in single-ring drivetrains to ensure a robust connection between the chain and the teeth on the chainring, by having alternating wide and narrow chainring teeth.<\/p>\n
It\u2019s not something that can be done with a drivetrain with multiple chainrings, because the position in which the chain will land when shifted between chainrings can\u2019t be determined, so the teeth in double and triple chainrings all have the same width, designed to mesh with the narrower inner-chain link.<\/p>\n
It\u2019s worth noting that the roller widths of derailleur chains for different numbers of speeds are almost the same: 2.38mm for 5- to 8-speed chains and 2.18mm for 9-speed and above. What changes is the width of the side plates.<\/p>\n
Chain width and \u2018speeds\u2019<\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>As the number of \u2018speeds\u2019 has increased, bike chains have become narrower, as shown by this 12-speed SRAM road chain.<\/span><\/figcaption> Warren Rossiter \/ Immediate Media<\/i><\/span><\/div>\n Things get more complicated with the width side-to-side of bike chains. As component brands have increased the number of speeds in their drivetrains, they\u2019ve added the extra gears needed in two ways: first, the freehub<\/a> that holds the cassette<\/a> in place on the rear wheel has been made wider.<\/p>\n
To accommodate the extra freehub width with the same distance between the rear dropouts, that\u2019s meant that the rear wheel has been ever-more asymmetrically dished. That\u2019s gone about as far as it can, which is why Boost spacing<\/a> has taken off in mountain bikes<\/a> to even out rear-wheel geometry.<\/p>\n
Second, cassette sprockets have got closer together and narrower. Chains have become narrower to match, which limits their compatibility between drivetrains with different numbers of gears. Therefore, you can\u2019t run a 12-speed chain with an 11-speed sprocket set, for example, and it means that if you\u2019ve got an 11-speed drivetrain you\u2019ll need an 11-speed chain.<\/p>\n
The width of chains for different numbers of gears, according to Park Tool is:<\/p>\n
- 13 rear cogs \u2013 4.9 mm<\/li>\n
- 12 rear cogs \u2013 5.3 mm<\/li>\n
- 11 rear cogs \u2013 5.5 mm<\/li>\n
- 10 rear cogs \u2013 6 mm<\/li>\n
- 9 rear cogs \u2013 6.5 to 7 mm<\/li>\n
- 6, 7 and 8 rear cogs \u2013 7 mm<\/li>\n<\/ul>
You\u2019ll see that there\u2019s a significant variation in width.<\/p>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Chains for singlespeed bikes and track bikes are normally significantly wider.<\/span><\/figcaption> Francesco Carta fotografo \/ Getty Images<\/i><\/span><\/div>\n Chains for singlespeed bikes<\/a> and track bikes are normally significantly wider than those designed for use with derailleur gears<\/a>. Typically, a track chain is around 9mm side-to-side. That\u2019s partly because there\u2019s more space for the chain at the rear hub and partly because the chain needs to be beefed up because it\u2019s under a lot of strain both when accelerating and decelerating.<\/p>\n
Chain compatibility<\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>SRAM\u2019s 12-speed MTB chains are compatible with the brand\u2019s 12-speed road groupsets.<\/span><\/figcaption> Alex Evans<\/i><\/span><\/div>\n In the past, chains of the same speed could typically be mixed between manufacturers, although this is generally not the case as you head up to modern 11-, 12- and 13-speed chains, where the designs are often more specific to the brand.<\/p>\n
For example, SRAM Eagle<\/a> 12-speed chains can\u2019t be used with 12-speed road rear derailleurs and vice versa. While you can mix some 11-speed Shimano and SRAM components, it often makes for a noisier drivetrain.<\/p>\n
Shimano 12-speed road groupsets<\/a> use the same Hyperglide+ chain as its 12-speed MTB groupsets<\/a>. It has specific design features to promote faster shifting to align with the shifting ramps on the cassette.<\/p>\n
Shimano also makes a Linkglide chain that is designed for use with electric bikes<\/a> with 10 or 11 speeds, although it can be used with its Hyperglide drivetrains as well as the ebike-specific Linkglide. This has a different link shape, designed to handle the extra power provided by the electric motor.<\/p>\n
There are brands such as Wippermann and KMC that make replacement chains that are generally compatible across all groupset makers, but it\u2019s worth checking their sites to ensure that a specific chain is rated for your groupset.<\/p>\n
Chain length<\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>A new bike chain will normally have more links than you need.<\/span><\/figcaption> Dave Caudery \/ Our Media<\/i><\/span><\/div>\n Chains are typically sold with around 110 or more links. That\u2019s more than needed for the majority of bike applications, so the chain typically has to be reduced in length to fit on a bike.<\/p>\n
High-pivot mountain bikes<\/a> are an exception, though, which typically require a longer chain length, and you may find you need to buy two chains.<\/p>\n
As we\u2019ve pointed out in \u201cHow do I replace a chain?\u201d below, the easiest way to make sure that it\u2019s the right length is to count the number of links in your old chain and, if your old chain worked satisfactorily, replicate it in your new chain. This is on the assumption that it was cut to the correct length originally.<\/p>\n
If you\u2019re fitting a completely new drivetrain<\/a> or altering the range of your cassette you need to be a bit more scientific and size your chain to get the correct length, as explained in our explainer on how to replace a bicycle chain<\/a>.<\/p>\n
Chain materials and construction<\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Most bike chains are made of steel.<\/span><\/figcaption> Getty Images<\/i><\/span><\/div>\n Most chains are made of steel \u2013 hence their tendency to rust if they get wet and aren\u2019t well lubricated. Some more expensive chains have a surface treatment to help avoid rusting, improve durability, lower friction \u2013 or just to look prettier. You can also buy chains made of titanium to save a little weight.<\/p>\n
KMC\u2019s top-spec chains, for example, are coated with titanium carbon nitride, which KMC says lowers friction, and come with black outer plates and inner plates in a range of different colours.<\/p>\n
The design of a chain\u2019s outer side plates varies significantly between makes and chain models. Often, there\u2019s some sort of ramping designed to help shifting, while more expensive chains will often have chamfered edges to the side plates rather than flat sides.<\/p>\n
Other features of some more expensive chains include slots in the side plates and hollow pins, both designed to save weight.<\/p>\n
Another option is a chain that is pre-treated to lower friction. Brands selling such chains include Silca<\/a> and CeramicSpeed<\/a>. They\u2019re typically rated to reduce drivetrain friction for a few hundred miles\u2019 use and possibly only in dry conditions, so they\u2019re definitely a race-day choice.<\/p>\n
Frequently asked questions<\/h2>\n
Are bike chains directional?<\/h3>\n
- Chain dimensions<\/a><\/li>\n
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