Though you won't get far without a chain on your bike, unless you have a belt drive or are riding a penny farthing, this is not a particularly interesting component.
Although a chain has a somewhat straightforward purpose, a lot of technology goes into a bike chain to make sure it meshes exactly with the chainrings on the crankset and the cassette sprockets at the rear, enabling smooth shifting when required.
This is a run-down of what you need to know about bicycle chains, including structural details, several "speed" chains, compatibility, chain length, and more. Either read on or use the links below to leap to the area you require.
What is the structure of a bicycle chain?
Made of a sequence of links mostly composed of side plates, pins, and rollers, a bike chain
A chain consists of a succession of links. Most chains repeat in a pattern whereby their wide and narrow links alternate for the length of the chain.
Every link contains two side plates, fastened together by rivets—also known as pins—and a roller rests on the shoulder of the outer link. Though these are typically removed from contemporary chains, some chains have separate bushing on either side of the roller.
A joining pin, commonly known as a "rivet," can be pushed part-way out of a link with a chain tool, then pushed back into the chain around another link from the other end to make the chain continuous.
Designed to interlock with the chainrings and cassette on the bike's drivetrain, a chain transforms your power from the pedals into forward motion. - Adam Gault / Getty Images
Campagnolo’s chains are joined with a bullet-shaped pin that’s longer than the chain is wide; the rounded end of the link pin is broken off (the technical term for this is ‘peened’) once the pin has been pushed into place in the chain.
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.
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.
Quick links are commonly used to close the chain. - Oli Woodman / Immediate Media
While other quick links—such as those used in Shimano's and SRAM's higher-spec chains—can't be detached once implemented because the quick link connection isn't as strong the second time around.
Some riders and mechanics, meanwhile, rework fast linkages without problems. You decide whether or not to take the chance.
What are the dimensions of a bicycle chain?
The distance between links is known as 'pitch'. - Getty Images
Although Team GB was believed to be utilizing ⅜ in pitch chains on their track cycles at the Tokyo Olympics, the usual distance between links, or pitch, of a bicycle chain is ½in (12.7mm). There are occasional tests with metric pitch (10 mm).
With a smaller space between the links, a bike chain's inner link is smaller than its outside link. By use of alternating wide and narrow chainring teeth, single-ring drivetrains guarantee a strong link between the chain and the teeth on the chainring.
With a drivetrain with several chainrings, the position in which the chain will land when shifted between chainrings cannot be known; thus, the teeth in double and triple chainrings all have the same width, meant to mesh with the smaller inner-chain link.
Interestingly, the roller widths of derailleur chains for various speeds are nearly the same: 2.38mm for 5- to 8-speed chains and 2.18mm for 9-speed and higher. The side plate width changes as well.
What are the dimensions of a bicycle chain?
Chain width and 'speeds'
Bike chains have gotten thinner as the number of "speeds" rises; SRAM's 13-speed XPLR chain clearly shows this.
The breadth side-to-side of bike chains complicates things even more. Component brands have added the extra gears needed in two ways as they have expanded the number of speeds in their drivetrains: first, the freehub holding the cassette in place on the rear wheel has been widened.
The rear wheel has been ever more asymmetrically dished to provide additional freehub width with the same distance between the rear dropouts. Boost spacing has exploded in mountain bikes to balance rear-wheel geometry since that is about as far as it can go.
Second, cassette sprockets have become thinner and closer together. Narrower chains fit better to match and restrict their fit between drivetrains with varying gear counts. Consequently, you cannot run a 12-speed chain with an 11-speed sprocket set, for instance, and so you will need an 11-speed chain if you have an 11-speed drivetrain.
Park Tool claims that the width of chains for various gear counts follows:
- 13 rear cogs – 4.9 mm
- 12 rear cogs – 5.3 mm
- 11 rear cogs – 5.5 mm
- 10 rear cogs – 6 mm
- 9 rear cogs – 6.5 to 7 mm
- 6, 7 and 8 rear cogs – 7 mm
You’ll see that there’s a significant variation in width.
Usually, chains for single-speed bikes and track bikes are rather wider. - Getty Images / Francesco Carta fotografo
Generally speaking, chains for singlespeed bikes and track bikes are far wider than those intended for use with derailleur gears. Usually, a track chain runs ninemm side-to-side. That's partially because the chain needs to be toughened up since it's under a lot of strain both when accelerating and slowing down, and partly because there's more room for the chain at the back hub.
Chain compatibility
The brand's 12-speed road groupsets fit SRAM's 12-speed MTB chains. /by Alex Evans.
While this is usually not the case as you head up to modern 11-, 12-, and 13-speed chains, where the designs are sometimes more particular to the brand, chains of the same speed could historically usually be combined between brands.
SRAM Eagle 12-speed chains, for instance, cannot be utilized with 12-speed road rear derailleurs or vice versa. Although some 11-speed Shimano and SRAM parts can be mixed, usually this results in a louder drivetrain.
The Hyperglide+ chain used in Shimano 12-speed road groupings is the same as that used in 12-speed MTB groupsets. Its particular design elements encourage faster shifting to coincide with the shifting ramps on the cassette.
Though it can also be used with its Hyperglide drivetrays as well as the ebike-specific Linkglide, Shimano also creates a Linkglide chain specifically for use with electric bikes with 10 or 11 gears. This features a distinct link form, intended to manage the additional power the electric motor generates.
Although some brands like Wippermann and KMC create replacement chains that are generally compatible across all groupset manufacturers, it's important to visit their websites to be sure a particular chain is rated for your group.
Chain length
Usually, a new bike chain will contain more links than you require. Dave Caudery
Usually supplied with roughly 110 or more links, chains usually Usually, the chain has to be shortened to fit on a bike since it is more than required for most bike uses.
One exception are high-pivot mountain bikes, which usually call for a longer chain length, and you could find you have to purchase two chains.
Counting the links in your old chain and then copying them in your new chain can help you to ensure that the correct chain length is what we have shown below. If your old chain worked satisfactorily, then so should your new chain. This is assuming that it was previously trimmed to the right length.
As advised in our explainer on replacing a bicycle chain, if you are building a totally new drivetrain or changing the range of your cassette, you must be a bit more scientific and size your chain to achieve the exact length.
Chain materials and construction
Most bike chains are made of steel. - Getty Images
Since most chains are composed of steel, their inclination to rust should they become wet and not be lubricated is clear. Some more costly chains feature surface treatment to help prevent rusting, increase longevity, reduce friction—or just to look nicer. To cut a little weight, you may also get titanium chains.
For example, KMC's top-spec chains are covered in titanium carbon nitride, which KMC claims reduces friction, and have black outer and inner plates in a spectrum of hues.
The exterior side plates of different chain versions have rather different designs. While more expensive chains will frequently have chamfered edges to the side plates rather than flat sides, often there is some kind of ramping intended to facilitate shifting.
Designed to save weight, some more costly chains also have hollow pins and slots in the side plates.
One further choice is a chain coated to reduce friction. Companies advertising similar chains include Ceramic Speed and Silca. They are absolutely a race-day choice since they are usually rated to lower drivetrain friction for a few hundred kilometers of use and maybe just in dry conditions.
FAQs
Q: Are bike chains directional?
A: The reply is "sometimes." Directionality depends on the brand and the groupings. Usually non-directional, older chains for lesser gear counts are Some are directional when you go into more recently published chains for more gears.
Sometimes the outer-side links may be slanted but not the inner-side links; in these circumstances, you should make sure they wind up on the outside when you fit a new chain for your bike. Regarding SRAM's 12-speed road chains, their flattop design indicates they must be put correctly from top down.
Check whether your chain is directed if it is connected together with a quick-link. Certain quick-links, including Shimano's 11- and 12-speed option, have an arrow pointing in the direction of the chain's travel.
SRAM's flattop 12-speed road chain is directional.
Q: When should I replace a chain?
A: A chain checker is the easiest approach to finding out when you should replace yours. Exactly when you should switch your chain will depend on where, when, and how you ride.
Chains will stretch, and side-to-side movement between links will also increase as they age. While the stretch can rapidly wear out cassettes and, more slowly, chainrings, the side-to-side movement can cause sloppy shifting.
Although we go into great length on when to replace your chain, the main lesson is that an 11-13 speed chain stretched by 0.5% should be replaced.
Because they are somewhat wider, chains that are 10-speed and under can be changed at 0.75 on a chain checker.
You will also have to change your cassette if your 11-13 speed chain stretches to 0.75 or your 6-10 speed chain to 1.0. As the rollers on the chain wear down, their mesh with the teeth on the cassette will not be ideal. Should your chain have worn further, you could also have to change your chain rings.
Replacing a chain instead of all three of the primary components—chain, chainrings, and cassette—on your drivetrain is cheaper. Changing your chain whenever it starts to exhibit wear will probably help you to extend the lifetime of your cassette and chainrings.
Roughly speaking, you could utilize three chains on one cassette as long as you catch the chain wear on schedule.
One easy instrument for monitoring drivetrain wear is a chain checker.
Before your chain gets overly stretched, change it to prevent needless wear on the chainrings and cassette.
Q: Which chain checker do I need?
A: You should get a chain checker appropriate for the speed your drivetrain runs at.
Although the cheapest solution is a small stamped metal tool that goes over a roller and has a tip that fits between the links farther up the chain, you can obtain really sophisticated versions, including the digital model from chain maker KMC and Park Tool's CC-2 Chain Checker.
If it can drop all the way into the slot between the links, your chain has to be replaced with most chain-checking instruments. Should it not, you still have life in your chain. The chain does not always run uniformly; hence, it is advisable to examine the chain at two or three sites instead of just one.
Some instruments, like the Park CC4, operate on a somewhat different basis, but nevertheless, you hold the gauge tip of the tool while keeping pressure before lowering it into a link to get an exact reading.
While digital chain checkers exist, a basic tool will do the job. - David Rome / Immediate Media
Q: How do I know what chain to get for my bike?
A: The speed chain your bike needs will depend on the cogged count on the rear cassette.
Once you know the speed your drivetrain is, you will have to locate a chain that fits the same number.
The different thickness of both chains will cause incompatibility problems when replacing an 11-speed chain with a 9-speed chain.
Although there is some room for interchangeability across the several speeds, it's recommended to replace like with like and choose a chain made for the number of speeds your bike runs on.
As long as they have the same amount of speeds, you occasionally can utilize chains from other manufacturers.
Sometimes you have to follow the chain your manufacturer of the drivetrain offers. Many third-party firms, including KMC, do, however, provide suitable chains for different groupsets.
It's always best to replace like with like when - Russell Burton / Immediate Media
Q: How do I replace a chain?
A: Usually you will need a chain tool to push out a chain rivet and remove your old chain in order to replace one.
After everything has been meticulously cleaned, you must thread your new chain through the drivetrain—including the jockey wheels on the rear derailleur.
To bring your chain to the proper length, first remove the appropriate number of links using the chain tool; next, combine the two ends.
More specifics abound in our post on replacing a bicycle chain.
A chain tool is an essential item for the home mechanic.
Q: How do I calculate the correct chain length?
A:
Counting the links in your previous chain can help you most easily determine the proper length if you are replacing a chain.
Measuring a chain using a tape measure won't always work since chains expand in length over time.
We advise you to install a chain on a bike for the first time from the front using the biggest chainring and sprocket of the cassette to ensure it is correctly positioned through any derailleurs.
Combining the two ends of the chain will provide the "zero point."
From here, you have to choose how many links to leave in the chain.
Shimano says this depends on the type of bike you ride and how the chain will be connected—quick links functioning as extra links.
Depending on whether your chain employs a fast link or a connecting pin, ridgid bikes—road bikes, gravel bikes, hardtails, and hybrids—will need 4 to 6 extra links.
To handle chain pull, full-suspension bikes need extra slack; Shimano advises 5 to 7 links depending on whether your chain employs a fast link or a connecting pin.
You can inject some slack into the system once you know the "zero point." Georgina Hinton / Immediate Media
Q: How do I care for a chain?
A: Reducing wear requires a clean and free of contamination chain. The best quick approach to accomplishing this is consistent usage of a chain cleaner. You should dry your chain once you have used a chain cleaning to prevent rusting. Apply then a thin film of chain lubricant.
Though you should pedal the chain 10 to 20 revolutions to let the lubricant work its way into the rollers and then wipe away any extra lube, follow the directions of the chain lube producer.
After careful degreasing and cleaning it beforehand, re-lube your chain shortly after a rainy ride to prevent it from rusting. Applying chain lubricant to a dirty chain would just help the chain to draw additional dirt; hence, it is not advisable.
We also go into great length on how to deep clean the chain and apply wax in our essay on how to wax a bike chain. You may also wax your chain.
Keep your chain clean and well-lubed. - Zetland Cycles / Immediate Media
Q: How do I clean a bicycle chain?
A: By cleaning your bike chain, you will eliminate the grit and dirt that wears out jockey wheels, chainrings, and cassettes before their time.
It also keeps your chain free-moving and increases re-lubing efficiency.
There are several methods of cleaning a bike chain; for those wishing to wax their chains, ultrasonic cleaners are currently rather popular.
For the finest advice on cleaning your chain, see that article; we have described in eight straightforward stages how to do it.
A clean chain will help increase the lifespan of other components. - David Caudery / Immediate Media
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