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Parts of a Bicycle Chain (Illustrated)

Chains are important in bicycles, this article features illustrations for parts of bicycle chains and understanding how they work to better care for your bikes.

Different types of chains for bicycle.

We do not give much thought to how a chain works to propel a bicycle until it’s not working properly or won’t stay on the sprockets. Although a bicycle chain looks simple, it can have 100 to 126 links. A bicycle chain is a roller chain that allows you to turn your bike’s front and rear sprockets to propel it forward.

Understanding how a bicycle chain is made will assist you when you need to replace yours because your bicycle is not going anywhere without a chain.

Are All Bicycle Chains Made of the Same Material?

A rear wheel of a mountain bike and stainless chain.

Most bicycle chains are made from alloy steel, which is very strong. However, performance bikes may have chains made from high-end alloy and have hollow parts, which save a lot of weight.

Price matters when buying a bicycle chain, and higher-priced chains are typically made from higher-quality materials. Conversely, lower-priced bicycle chains may be made from lower-quality steel.

Bicycle chain manufacturers keep their metal blends as carefully guarded as big soda manufacturers. Some bicycle chains are made of soft steel alloys, and others ‘hard chrome’ or other metal blends are formulated for this purpose.

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Coatings are also a factor in the price of bicycle chains. Like the blend of metals from which they are made, some chains are coated in materials such as “nickel plate” and titanium nitride plating.”

Components of a Bicycle Chain

Your bicycle chain size must match the tooth span of the front sprocket and rear cog teeth and their width. Even the best bike chains will stretch over time, and will skip over teeth, and can damage the gears of your bike.

As you can see in the diagram, a link comprises more than one part. Each chain length consists of:

  • Outer plate
  • Pins (rivets)
  • Bushings
  • Rollers
  • Inner plate

Mountain bike chain components illustrated in a chart.

Drive components that work in conjunction with the chain include:

  • Cranks
  • Pedals
  • Front sprocket
  • Chainrings
  • Cogs (aka – cassettes, a grouping of gears)
  • Derailleur

Are the Links of a Bicycle Chain the Same?

Thin type bicycle chain made of alloy.

The Master link is not the only link that is different from the others. For example, bicycle chains can have inner plates with a fixed split bushing paired with a narrow roller. Although the master link is made to be removed easily, they are not all created equally.

When a Shimano chain is disconnected, it will need new rivets to rejoin the ends, which requires a unique tool, and you will need to replace the old rivets, as you cannot use them again. However, chains made by SRAM use what they call a “Powerlink,” which makes disconnecting the ends of your chain relatively easy.

Other chains often use a clip that locks into a slot in the pin, which holds the two chain ends together.

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There are only a handful of bicycle chain manufacturers. Although they are universal in size and fit, replacing parts with original equipment will assure success.

Are All Bicycle Chains the Same length?

The beauty of a bike chain is that you can shorten or lengthen it to fit your bicycle. The special link that enables you to change the length of a bicycle chain is the master link. It is also called a quick-link or clasp hook. This link allows you to disconnect the chain, remove the links you do not need, and reattach the chain ends.

Whether you have a bike with one, 3,18,21,24, or 27-speeds will determine the length and width of the chain you need. You will need to use your old chain to determine how long you need to make your new chain. Chain lengths vary from 100 links to 126 links, and the number of gears your bicycle has is a big factor in the length of the chain.

Are All Bicycle Chains the Same Width?

Bicycle chain with different sizes and width.

Although the length of each link is the same, which is one-half of an inch from rivet to rivet, the width is not. Bicycle chains are made to fit the one-half-inch span between the teeth of the sprocket. However, the width of sprockets varies, as do the chains that fit them. Bicycle chains are available in widths of 3/32” (2.4mm), 1/8” (3.2mm), 5/32 (4.0 mm), and 3/16s of an inch (4.8mm) wide.

Each bike will use a different width chain, and 1/8” chains are generally used on a single speed, two sprocket bicycles. The other sizes are used on multi-speed bikes. Generally, the more sprockets your bicycle has, the narrower the chain will be. The heaviest chains, which are 3/16s of an inch wide, are used on adult tricycles and bicycles used to transport freight.

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BMX Bicycle Chains are Different than Road Bicycles

A young man with his BMX bicycle.

Some BMX bicycles use a traditional chain. Its configuration is two inner and outer ‘half-links’ of the same length and is the most common chain type. However, the half-link chain, also made from identical lengths, has a thin and thick end.

Because BMX bicycle chains are made this way, a half-link can be removed instead of a full link, which means you can adjust the chain more accurately.

The width of a BMX chain is usually the standard 1/8th inch; however, racers often use a 3/32 inch chain to save weight. BMX chain lengths come in 96, 98, and 112 links. Like any other bicycle, you will need to measure the length of your chain to get the size correct.

Bicycle Chain Maintenance Will Save it From Wear.

A woman working in a bike shop.

The biggest enemy of a bicycle chain is friction. The coatings applied to chains are formulated to reduce friction and prevent rust. However, your bicycle chain will need a light layer of lubricant from time to time.

Not all lubricants are the same, and it is best to use one made to use on bicycle chains. By oiling your bicycle chain regularly, and adjusting it when needed, you can extend its useful life and that of the front sprocket and cogs.

A worn chain can wear on them until they too need replacing and at that point, you may need to replace all of the moving drive parts, which is an expensive, time-consuming process.

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