Bicycle chain for 21 speed

Bicycle chain for 21 speed DEFAULT

Chain Length Sizing

Aug 25, 2015 /Chain Repair and Service

Replacement chains for bicycles are usually longer than you need. This repair help article will take you step by step through the different methods of sizing a bike chain.


Preliminary Info

Before we begin the chain sizing process, let’s first define the two types of multi-speed bicycle chain. There are chains that use a quick link and chains that use a special connecting rivet chains. Quick link chains use two removable outer plates to connect the chain. Connecting rivet chains use a special rivet to connect the chain.

Quick link (L) and connecting rivet (R) chains

Check & Remove Chain

Before removing the old chain, verify that it is the correct length.

Shift the bike into the largest chainring and rear cog. The chain should be long enough to make this shift with two slight bends at each pulley of the rear derailleur.

Slight bend at each pulley

Next, shift to the smallest chainring and sprocket. There should be no slack in the chain, and the derailleur should not pull so far back that the chain contacts itself.

Correct derailleur position and chain tension

Next, remove the rear wheel. This will take tension off the chain and give you better access to the chain. Inspect the chain for a master link.

Master link

Quick Link Chains

If a quick link, sometimes called master links, are present, use a master link pliers such as the Park MLP-1.2 to disengage the link. If you have a chain tool and your chain is worn out, you can ignore the master link and simply cut the chain using a chain tool.

Disengage with MLP-1.2

Connection Rivet Chains

Connecting rivets will appear visually different from other rivets. When selecting a rivet to break, be sure that it is at least a couple of links away from any connecting rivet already installed in the chain. Install the chain tool and bring the driving pin of the chain tool into contact with the connecting rivet. Ensure the chain tool pin is driving in a straight line into the chain rivet. Turn the handle with force and drive out the rivet, then remove the chain.

Bring tool into contact with rivet

Bring tool into contact with rivet

Closeup of chain tool with arrow demonstrating driving a chain rivet with the pin straight and centered

Drive out in straight line


Sizing to Original Chain

If the old chain is an acceptable length, lay it next to the new chain. Always line up outer plates with outer plates or inner plates with inner plates. This example is incorrect because we have an end with outer plates being compared to an end with inner plates. Insert the master link to get a true side by side comparison. Take care to match them rivet by rivet noting that old chains will lengthen as they wear.

Add master link for comparison

Add master link for comparison

Match rivets on used chain to new chain

Match rivets on used chain to new chain


Largest Cog & Largest Chainring Method

The method of chain sizing depends upon the range of gearing in the system. For bikes with rear sprockets 36 teeth and smaller, the common system is to measure using the largest rear sprocket and largest front ring as a reference. Two rivets are added to this (one-inch) for the place to cut the chain.

If the rear sprockets are 42 teeth or larger, such as on dedicated 1X system (“one-by), extra chain is added as described below.

First, shift the front derailleur over the largest chainring and the rear derailleur to the smallest cog. Begin by wrapping the chain around the largest rear cog. If the new chain has one end with an outer plate, it should be routed toward the front chainring. Pass the chain end through the front derailleur cage onto the largest front chainring and hold it at about the five o’clock position.

Pass chain through front derailleur

Pass chain through front derailleur

Hold at five o'clock position

Hold at five o'clock position

If the chain uses a master link, install half of the master link. This will account for the extra half inch the master link provides. With this plate installed, the rest of the process is the same for master link and connecting rivet chains. Pull the lower section of chain snug and engage it on the front chainring.

Pull lower section snug

Pay special attention that the chain is fully engaged on the largest rear cog for accurate sizing. You will bypass the rear derailleur entirely for this step and extra length will be added later to account for this. Find the closest rivet where the two chain ends could be joined. You will match inner plates to outer plates in order to join the chain. The rivet closest to where the chain can be joined is the reference rivet. From the rivet we add two additional rivets.

Reference rivet

Reference rivet

Add two rivets

Add two rivets

This is the cutting point for your chain. It can occur that, when we pull the lower section snug, an outer plate meets an outer plate. This cannot be the reference rivet because the chain cannot be joined here. Add one rivet. This becomes the reference rivet and from here we add two additional rivets, cut the chain with a chain tool, and the chain is sized.


Largest to Largest plus 2 inches for Dedicated 1X

The dedicated 1X systems use a single front ring in combination with a wide range of rear sprockets. Derailleur manufacturers use large rear 42 tooth and larger sprockets. These require a longer chain compared to the bikes using less of a wide range.

Dedicated 1X shifting system

Without passing through the rear derailleur, route the chain over the front ring and the largest rear spocket. Determine the shortest length where a chain would connect inner and outer plates. From this point, count 4 rivets as the point to shorten the chain. This is an addition is 2 rivets (1-inch) more than non-dedicated 1X system.

Sizing 1x add 4

Exceptions & Considerations

Another consideration deals with rear suspension. The distance between the rear cogs and front chainrings will change as the suspension compresses and moves for bumps. To account for that, disconnect the shock, and compress the linkage.

If the bike uses a chain guide, make sure it is routed through the system before determining chain length. Add the same two rivets before to establish the cutting point.

Route chain through guide
Disconnect shock

Disconnect shock

Compress linkage

Compress linkage

Next article in this series

Chain Replacement: Derailleur Bikes View Article

Related articles

Chain Length Sizing: Campagnolo® View Article


Chain Compatibility

Feb 17, 2017 /Chain Repair and Service

This article will review the basics of bicycle chain compatibility to help you know how to choose the right chain for your bike.


Preliminary Info

Bicycle chains are made of multiple pairs of steel outer plates and inner plates held together by rivets. A roller separates each pair of inner plates. The rivet (pin) is pressed tightly through both outer plates. The rivet then pivots freely on the inner plates and roller.

The component parts of a chain — A: side plates; B: inner plates; C: rivet; D: rollers

All modern bicycle chains are made to the “one-half inch pitch” standard, meaning from rivet to rivet is nominally 0.5 inches. The sprocket teeth are cut for this same one-half inch standard to accept bicycle chains. However, this does not mean all makes and models of chains are interchangeable.

There are two basic types of bicycle chains: “one-speed” chains, and derailleur chains.


One-Speed Chains

The common one-speed chain is designed for bikes with one sprocket on the crankset and second sprocket on the wheel. The width of the roller is nominally 1/8″ wide (3.3mm). The one-speed chains are not designed shift on the multiple rear cog sets of derailleur bikes.

There are rear hubs with multiple internally geared speeds, but the chain is still commonly called a “one-speed” chain. They are also referred to as “eighth-inch chain.” The 1/8″ chain will measure approximately 9mm across the rivet.

1/8" chain at the top, derailleur chain at the bottom

Some freestyle bikes use a wider sprocket and a wider 3/16″ one-speed chain. The idea is that this wider chain provides longer chain life for the purpose “grinding,” which is sliding down a rail or other long fixture on the chain.


Derailleur Chains

Derailleur bike chains are designed to be moved from sprocket to sprocket, and come in many different design standards. When selecting a chain, the first consideration is the number of rear sprockets. The rear cog sets have been made with 5, 6, 7, 8, 9, 10, 11, or 12 sprockets. As the number of cogs on the rear hub increases, the spacing between cogs tends to be reduced. Consequently, chains tend to get narrower as the number of rear cogs increases.

Nominally derailleur chains are called “3/32-inch chain.” However that is not a true measurement, as modern derailleur chains can vary from that sizing.

Some nominal widths measured across the rivet between chains are:

  • 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
Various derailleur chains in different standards

In addition to the chain working on the rear cogs and rear derailleur the chain must be compatible with the front chain rings. Front cranksets are also designated for varying “speeds” to give an indication of the right width chain to use. The spacing between front rings for a 8 or 9 speed chainring set will be relatively wide. Using a narrow 10 or 11 speed chain may result in the tendency for it to fall between the two rings during a shift.

Drivetrain manufacturers design their chains to work as a system with the derailleurs, rear sprockets, and shift levers. Chains can vary in side plate shape, sizing, and height. Differences can cause variations in shifting performance between brands and models.

Different shaped side plates among various manufacturers

Additionally, chains will vary in the quality of steel used. Better chains that are more durable and longer lasting tend to have harder rivets. Riding a bike tends to wear and thin the rivet as it is pulled against the inner plates.


Final Notes

When in doubt about chain selection, it is usually best to stick the the drivetrain manufacturers chains. It does get more complex when components become mixed. For example, a bike may have a SRAM® chain but Shimano® derailleurs, a Sun Race® cassette, and MicroShift® shifters. Some chains can be used between different brands. Consult a professional mechanic for recommendations. There are certainly times that chain selection is an “educated guess.”

Next article in this series

Chain Replacement: Derailleur Bikes View Article

  1. Srt 300 price
  2. Knock me up
  3. Sonic.exe game
  4. Corsair psu rgb

There is no universal bike chain that would fit all types of bikes. Bike chain sizes vary based on several factors. In my previous article, I already have discussed the types of standard bike chains. Anyhow, I thought that we need a separate article on bicycle chain sizes.

If you are replacing your bike chain by yourself, you need to be aware of the differences between bicycle chains.

In this article, we will be discussing different lengths and widths of bike chains. We’ll also discover an equation for determining the proper length of a standard bike chain, review a chart of bike chain sizes, and finally, we’ll answer some of the burning questions.

So, let’s start with the bicycle chain size chart and size guide.

As an Amazon Associate I earn from qualifying purchases made through links in this post at no extra cost to you.


Bike Chain Size Variables

Link Lenght (Pitch)

The bike chain link pitch (distance between pin centers) is standardized and equals 1/2 inch or 12.7 millimeters. Historically there were also other pitch sizes, but the 0.5-inch pitch is standard these days.

Length (Total Length)

The total length of the bike chain is calculated by multiplying the number of links with a 1/2 inch link pitch.

I have seen chains with 100 up to 126 links.

I analyzed a list of best-selling bike chains on Amazon and found out that the most popular chain length is 116 links.

# of LinksModels Available

You can always shorten your bike’s chain. But it is not easy to increase the length of a bike chain. So, try to find an adequate size.

Internal Width

There are 4 sizes of the internal width of bike chain – 1/8″, 3/32″, 11/128″, and 5/32″:

  • 1/8″ (3.2mm) – some of the bikes with a single rear sprocket
  • 3/32″ (2.4mm) – some of the bikes with a single rear sprocket, bikes with 5-8 rear sprockets, and derailleurs
  • 11/128″ (2.2mm) – bikes with 9-12 rear sprockets and derailleurs
  • 5/32″ (4.0mm) – freight bicycles and tricycles.

In other words, if you have a heavy-duty cargo bike or tricycle, you need a 5/32″ chain.

If your bike is equipped with the derailleur, you need a 3/32″ or 11/128″ chain.

If you have a single-speed or internally geared bike, you need either 1/8″ or 3/32″. You should get the correct size, but if it is not possible, you can get the 1/8″ because it has limited compatibility with the 3/32″ sprocket.

External Width

When you are shopping for a new chain for your multi-speed derailleur bike, the external width is another factor you should keep in mind. The proper width is determined by the number of rear sprockets your bike has – the more rear sprockets are spaced close together, the narrower chain should be used.

The external width of the chain is not something you should worry about in the case of a single-speed or single rear cog bike.

Bike Chain Size Chart

More often, cyclists like me end up with a lot of options in hand. We even turn confused about what to choose. So, for helping in properly selecting bike chains, I am sharing a bike chain size chart below.

While single-speed bike chains have different measurements, the size chart below is applicable for most geared bikes. The chart combined with this guide and equation should be adequate for determining the bike chain’s size.

Drivetrain*External Width, inExternal Width, mmInternal Width, in
5 / 6 / 7 / 8 speed9/32″7.1 – 7.3mm3/32″
9 speed1/4″ – 9/32″6.5 – 7.0mm11/128″
10 speed1/4″ – 9/32″6.0 – 7.0mm11/128″
10 speed narrow7/32″5.88mm11/128″
11 speed7/32″5.5 – 5.62mm11/128″
12 speed13/64″5.3mm11/128″

* Number of rear sprockets


  • there is some variance between chainsets from different manufacturers, so it is advised to get a chain from the manufacturer of your bike’s chainset
  • you can use a narrower chain than your bike specs call for, but remember that thinner chains are more expensive and less sturdy
  • if you use a narrow chain with a worn-out chainset, the chain can fall between the sprockets

How To Find The Proper Length Of the Chain?

Use The Old Chain

If your old chain still holds a great shape with proper length, you can use it for comprising when buying your new chain.

Just lay the new chain besides the original chain. Outer plates should be aligned with outer plates and inner ones with inner plates. You can use the master link to get a proper comparison.

If you have used the chain for a prolonged period, the chain will most likely be subject to the chain stretch, so this method could not provide the correct data.

Largest Cog and Largest Chainring Method

On the contrary, if you don’t have your old chain, you can also use the largest cog and largest chainring method to measure your bike’s chain size.

The process is as follows:
  1. Change the front derailleur on the biggest chainring and the back derailleur on the smallest cog.
  2. Start by covering the biggest back cog with the chain.
  3. If you have one end of the new chain on the outer plate, you should route it towards the front chain.
  4. Take the chain and pass it through the front derailleur cog and keep it put in the 5 o’clock position.
  5. If you have a master link, install half master link.
  6. Take the lower section and bring it close to the previously held front chainring.
  7. Pay proper attention and detect the reference rivet where your chain’s both end matches with maximum tension.
  8. Add one rivet with the reference rivet, and the newest one becomes their reference rivet. You’ll need this as you won’t be able to join on the earlier reference rivet.
  9. Cut the chain on the additional rivet to the new reference rivet by using a chain tool.

There are a few exceptions. You need to add four rivets with the reference rivet in SRAM derailleur with 11 or 12-speed cassettes.

Besides, you also need to consider the rear suspension. As your bike pushes the rear suspension, the distance between chainring and cogs will decrease. For proper setting, disconnect your bike’s rear suspension shock and set up the linkage.

Finding Chain Length From Equation

Bicycle chain lengths are whole integers. They cannot be fractions as they consist of outer and inner plates.

We can find the length of the bike’s chain using an industrial equation for derailleur chains.

For measuring the length of bicycle chain size, you need to do the following:

  1. Count the number of teeth on the biggest front sprocket and largest rear sprocket. You can find the numbers printed on the sprockets too.
  2. Next, you need to measure the distance between the crank bolt’s rear axle and midpoint.
  3. Measure the distance to the nearest 1/8 inches and convert it into decimals.
  4. Then, you use the equation for finding the length of your chain.

Here is a simple equation of bike’s length:

L = 2 (C) + (F/4 + R/4 + 1)


L= Length of the chain in inches.

C= Chainstay length in inches from the above-described steps.

F= Number of Teeth on the biggest front sprocket.

R= Number of Teeth on the biggest rear sprocket.

When you determine the length, it may contain fractions. Just round it off to the nearest whole integer.

Anyhow, this equation is not applicable for bikes with extreme variation in chainring sizes or short chainstays. In such cases, you need to use a complex and rigorous equation which is:

Chain length, L = 1 + 0.25 X (F+R) + 2 X

Frequently Asked Questions

How do I know my bike chain size?

You can know the size of your bike chain size from the above bike size chart. You can also manually detect the size by using the equation for the bike chain size stated above.

What is the standard bike chain size?

Standard bike chain size stands for the regularly acceptable bike chain standard dimension. It mainly includes the sizing of inner and outer width along with size charts.

For example, single-speed chains have standard 1/8 inches width, while multi-speed chains with 5-8 speeds have an inner width of 3/32 inches. Bikes with 9-12 speeds have 11/128 inches inner width. The outer width also varies based on speeds. We have documented a standard bike chain size chart above.

What size chain should I get?

You should get the chain size that aligns with your bike. There are equations and charts for determining the size. Read the whole article for details.

Are all bicycle chains the same size?

No, all bicycle chains are not the same size. Size varies on the bike’s numbers of sprockets, speeds, the distance between the front chainring and rear cogs, and the number of teeth on them.

What are the different chain sizes?

Chains sizes are different from each other based on the type of vehicles. Besides, they are also variable when considering the interior structure and design of similar types of vehicles. Mainly, bicycle chains come in 3/32 inches, 1/8 inches, 5/32 inches, 3/16 inches roller widths.

How do you size a 1×11 chain?

You can size a 1×11 chain by following several steps. These steps are listed below:

  1. Change the back derailleur on the smallest cog.
  2. Start by covering the biggest back cog with the chain.
  3. If you have one end of the new chain on the outer plate, you should route it towards the front chain.
  4. Take the chain and pass it through the front derailleur sprocket and keep it put in the 5 o’clock position.
  5. If you have a master link in the chain, install half master link.
  6. Take the lower section and bring it close to the previously held front chainring.
  7. Pay proper attention and detect the reference rivet where your chain’s both end matches with maximum tension.
  8. Add four rivets with the reference rivet, and that will be your new cutting point.
  9. Cut the chain on the cutting point by using a chain tool.

Are 6, 7, 8-speed chains the same?

No, they are not the same. You can use a 7.1 mm wide 8-speed chain on all of them, but the Chain for 6 and 7 speeds is wider than 8. So, you can use an 8-speed chain on 6 and 7. But you shouldn’t use 6-speed chains on 7 and 8 or 7-speed chains on 8.

Do bike chains have directions?

Yes, some of the bike chains have directions. You can detect the direction by determining any printed letters or logos on the chain. The outer side of the text should be on the drive side.

What is the difference between 10 and 11-speed chains?

The significant difference between the 10 and 11-speed chains is the external chain width. Though they both have almost similar width and cassette teeth, 11 speed’s chain width is 5.62 mm while the 10-speed chain’s width is 5.88 mm. Are they interchangeable? Sort of. You can use 11-speed chains on 10-speed bikes (and pay the premium price because the narrow chains tend to be more expensive). But a 10-speed chain will likely be too wide for the 11-speed gear set.

Can you use the regular bicycle chain on the motorized bike?

Yes, you can use the regular bicycle chain on the motorized bike’s pedal drive. A motorized bike also uses a second chain as a drive. The size #415 drive chain, e.g., King PRO COMPANY bike chain, is thicker and heavier and is explicitly designed for motorized bikes. Coming with a durable and versatile design, it can be used in 2 stroke bikes.


We have tried to give all the ideas that you need for a DIY chain replacement. Anyhow, still, there might be some exceptions and confusion. If required, you should consult with professionals for further details.

Related Articles

You Might Also Like

Chain quick links: A quick guide to easy connection


Speed 21 chain bicycle for


How to Size a Bicycle Chain


You will also like:


1570 1571 1572 1573 1574