Are All Bike Chains The Same Width?

There’s an incredibly vast catalog of chains that you can choose for your bike. But which one should you choose? Does it really matter? Will a different chain even fit? 

Single-speed bikes and bikes with 6, 7, or 8 speeds on the rear cassette can usually share chains. Bikes with 9 or more speeds usually cannot share chains with bikes of different numbers of speeds or bikes with drivetrains made by different (and sometimes even by the same) manufacturer(s).

Let’s take a look at what goes on with your bike chain, why different chains are made differently, and why you should follow the manufacturer’s recommendations and get a chain that matches your cassette, even if it’s more expensive.

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Are All The Bike Chain Sizes The Same?

No, bike chains are not all the same size. While the distance between rivets (or links) in each chain is constant at 0.5 inches, the width of the chain varies a lot between different types of bikes

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Single-speed bikes usually use chains that have a 1/8″ internal width, although the external width might vary. 

Bikes with simple rear derailleurs use chains with 3/32″ internal width, making these chains too narrow to interface with the cogs found on single-speed bikes.

Bikes with more complex gearing arrangements use more specific chains. Bikes with 9, 10, 11, or 12 speeds in the back use chains with inner widths of 11/128″, making them incompatible with 6, 7, and 8-speed systems. 

While bikes with 6,7, or 8 speeds on the rear cassette can almost always share chains, bikes with 9 or more speeds usually cannot share chains with bikes of different numbers of speeds or bikes with drivetrains made by different manufacturers. 

In other words, your 1×11 Shimano bike shouldn’t use the chain from your 1×10 Shimano or your 1×11 Campagnolo drivetrains.

This is because as the number of cogs in the back grows, the chain has to be thinner to accommodate the smaller amount of space between cogs. In order to achieve this, chain manufacturers make the outer width of their chains thinner and thinner. 

This results in some pretty impressive engineering, but it also means that chains start to have unusual shapes and configurations that can cause problems with cassettes and derailleurs of other brands. 

This doesn’t apply to your chainring. In most cases, your chainring’s brand doesn’t matter as long as it’s compatible with the inner width of your chain. In other words, a chainring that works with 9-speed drivetrains should also work with 12-speed systems.

A few bikes, most notably cargo bikes and trikes, use chains that are 5/32″ wide. These chains are better able to withstand torque from carrying big loads.

Income School

The recent surge in e-bike popularity has driven manufacturers to mark some chains as “e-bike rated.” These chains are the same size as normal bike chains. The big difference between an e-bike chain and a normal chain is that an e-bike chain is designed to handle a lot more torque. 

E-bikes with mid-drive motors can output ridiculous amounts of torque and can easily snap a “normal” chain, even with a casual rider who isn’t trying to go particularly fast. 

This makes it important to find a chain that’s designed for the amount of stress that you put on your bike, even if you can find other chains that fit.

Can I Use A Single-Speed Bike Chain On A Multi-Speed Bike?

While a handful of exceptions might exist, in most cases you cannot use a single-speed bike chain on a multi-speed bike. Single-speed bike chains have wider gaps in the center than multi-speed bike chains

This means that the chain might get stuck in your derailleur, damage your cogs, and rub against parts of your bike while you ride. In a lot of cases, you’ll have a lot of trouble threading the chain through your derailleur. 

Do NOT try to fight against your bike and force one of these chains on. You run the risk of causing hundreds of dollars in damage to your cassette, snapping off your derailleur or damaging the components, or just jamming up your drivetrain while you ride.

Are All Bike Chains Interchangeable? Which Ones Are Interchangeable?

In general, you can use a couple of quick rules to figure out which bike chains are interchangeable with each other.

First, if you have a single-speed bike, chains from other single-speed bikes will usually work. 

You’ll want to do a bit of detective work before you go on any long rides, however. Examine how the chain sits on the cogs and listen to the chain as you turn the pedals. If your chain isn’t rubbing up against anything, making noise, or otherwise sitting oddly on your bike, you’re good to go.

If you have a bike with 6, 7, or 8 cogs in the back, you can usually use a chain from any other bike with 6, 7, or 8 cogs in the back. Until you hit 9 speeds in the rear, bike chains have fairly uniform outer and inner widths. 

This means most entry-level mountain, hybrid, and road bikes all have interchangeable chains. These chains have standard shapes and aren’t particularly brand specific, so you’re good to mix and match components from different brands. 

You can borrow the chain from a 3×7 Schwinn and put it on your 2×8 Trek with no issues. Be sure that it’s a clean and lubricated chain without excessive wear before pillaging it, however. You can still run into problems from using a dirty, stretched, or unlubricated chain.

Bikes with 9 or more cogs in the back start to get complicated. Drivetrains with different numbers of gears will use chains with different outer widths. 10-speed chains range from 7mm to 5.88mm, while 13-speed chains are just 4.9mm wide. 

Different manufacturers use chains that vary in design, width, and shape, so it’s important to match your chain with both your cassette and your derailleur. A Shimano chain won’t play nice with a SRAM derailleur or a KMC cassette. 

Even drivetrains made by the same manufacturer can use different chains. Shimano 10-speed systems might use wide 7mm chains or narrow 5.8mm chains.

On many 9+ speed drivetrains (especially Shimano systems), your chain needs to be installed in the right direction. If there are markings on one side of your bike chain but not the other, install that side of the chain facing out.

To summarize: single-speed bikes can use other single-speed chains. Bikes with 6, 7, or 8 cogs in the back can share chains. Bikes with 9 or more rear cogs use chains that are specific to their cassettes and derailleurs. 

Make sure you’re using a chain made by the brand that made the rest of your drivetrain and do some extra research to make sure that it’s the right one for your bike.

Do I Need a different Chain if I Change the Chainring and/or Cassette?

Chains have two widths: the width of the outside of the chain, and the width of the inside part of your chain where your cogs go. 

Single-speed chains use 1/8″ inner widths; 6, 7, and 8-speed chains use 3/32″ inner widths, and 9+ speed chains use 11/128″ inner widths.

As far as the chainring compatibility goes the inner chain width matter. Chainrings are compatible with these three different inner widths. You can completely ignore the gears in the front; it doesn’t matter if you’re riding a 1x, a 2x, or a 3x.

If you’re running a single-speed system, the outer width of your chain matters less than it does on bikes with gears. As long as your chain doesn’t hit the rest of your bike, you’re probably good, even if your new chain has a different outer width.

If you’re running a 6, 7, or 8-speed system, and you want to change the cassette and the derailleur, it is unlikely that the outer width of your chain will change. Almost all of these drivetrains use chains that have the same outer widths, so you won’t have to change the chain.

If you’re switching from a 9+ speed system to another 9+ speed system, however, you’ll definitely want to change your chain. A change in the cassette and derailleur will require you to use a chain with a different outer width.

How Do I Know My Chain Width? How Can I Tell Which Chains Fit My Cassette And Derailleur?

The best way to measure your chain’s width is to simply use a ruler (or ideally a micrometer). 

You can get a very good idea of your chain’s width by placing it on top of a ruler and measuring both the inner and outer widths. If you’re having trouble getting an exact number, consider taking a high-definition picture and zooming in to produce a more accurate measurement.

If you can’t measure your chain (or you don’t want to), use the information above to make an educated guess about the width of your chain. On a 6, 7, or 8-speed bike, you’ve probably got a 3/32″ inner width and can use any 6, 7, or 8-speed chain. 

If you’ve got a 9-speed bike or higher, use your cassette and derailleur to figure out the width of your chain. You should be able to figure out the manufacturer’s recommendations for compatible chains and go from there.

Sam Benkoczy

Hi, I'm Sam. I own and maintain 6 e-bikes, 15 regular bikes (road bikes, folding bikes, hybrid bikes, city bikes among others). I learned about bikes from my local bike mechanic as well as from bike maintenance courses. I love being out there in the saddle, and using my bike as a practical means of transportation. You can also find me on my YouTube channel at youtube.com/bikecommuterhero Say hi to me at sam@bikecommuterhero.com.

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