5 Signs of Worn Mountain Bike Chain: (Definitive Guide For 2023)

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Are you aware of the signs of worn mountain bike chain?

If you aren’t, then it’s important that you gain the necessary knowledge required to assess whether it’s time to replace your mountain bike chain with a new one.

Get ready to get some interesting insight on mountain bike chain wearing.

Let’s dive right in!

Some Interesting Facts About MTB Chain Wear

Mountain Bike Chain Wear Causes
MTB Chain Wear Causes

Did you know that every minute of pedaling your mountain bike puts about 44 thousand chain pieces in motion?

This would lead to approximately 320,000 events of sliding surface friction.

While this information is great to understand the level of wear that a mountain bike chain is prone to, there is more than what meets the eye.

A mountain bike chain comes in close contact with several elements, which add to the process of wearing.

As the chain’s pins and inner links start wearing, the length of the chain, which is called the pitch, increases.

This process leads to chain stretch, wherein, the chain does not actually stretch, but elongates, as it starts to stay loose on the links.

The industry standard pitch on a multi-speed bike chain is suppose to be 0.5-inch or 12.7mm (gap between the pins).

How To Check For Signs of Mountain Bike Chain Wear

Signs of Mountain Bike Chain Wear
Signs of Mountain Bike Chain Wear

There are different methods to check for signs of a worn mountain bike chain.

While veterans just lift the chains rings and arrive at whether the chain has started wearing or not, there are tools available for those who prefer more scientific ways of measuring chain wear.

If you opt for the methods that use tools, get hold of CC-3.2 and CC-2 chain checkers to quickly determine the chain wear.

The 5 most popular methods to check a worn mountain bike chain are discussed below:

Method 1: Chain Lifting Method

In this method, the biker has to lift the chain off the chainring in the front and shift to the smallest cog on the rear and the largest in front.

After shifting the chainring as mentioned, lift the chain off the chainring.

If there is more slack than usual, it indicates that the chain has started wearing.

If the slack is more, the chances are, the chain has already worn out and you need to replace it at the earliest, to prevent further damage to the cassette and other derailleur components.

This video demonstrates perfectly how to identify a wearing MTB chain, so check it out for a visual demo (Time stamp 2 min 40 sec onwards!)

Method 2: Use A Ruler

This is another method to roughly estimate the chain wear. All you need is a ruler for this method.

Pick a rivet and mark it at the zero mark. Carefully count 24 more rivets. If the last rivet falls on the 12” mark, then you can conclude that your chain is still performing well, and has not worn out.

On the other hand, if the last rivet falls 1/16” ahead of the 12” mark, it indicates that the chain must be replaced soon.

Check out this video which demonstrates how to measure a bike chain wear with a ruler.

Method 3: Use CC-3.2 tool

Using a tool will always give you a more accurate result.

A CC- 3.2 chain checker tool is one such tool that will help you quantify chain wear.

In order to measure using the tool, place the end of the tool with a 0.5 mark.

The ideal way to measure is against the roller, and hence you must ensure that the hook end is installed on a link with inner plates.

The other end of the hook must be installed into the chain.

Follow these video instructions for accurate results.

Method 4: Use CC-2 tool

The CC-2 Chain checker tool can be used to effortlessly check the extent of chain wear.

While using this tool, the rear stud must be inserted between two outer plates whereas the front stud should go in between two inner plates.

While you do this, you can eliminate the slack by pushing lightly on the lever, till it reaches a distinct stop.

Make sure that the tool isn’t forced beyond the point it stops.

You can find the reading which would tell you an almost accurate percentage of the chain wear.

Method 5: Use CC-4 tool

The CC-4 tool is the most accurate tool available to check a mountain bike chain wear on most 5-12 speed MTB chains.

Whether it is SRAM or AXS chain (12-speed), this chain checker will do its job well.

The checker comes in contact with the chain in three places. It accurately displays when the chain reaches .5% and .75 % wear.

This is the level of wear at which manufacturers normally suggest chain replacement.

To improve the accuracy of the reading, you must keep the gauge tip above the chain while lowering the chain checker into the chain.

Apply tension on the tiny section of the chain and maintain. The place where the gauge tip falls will tell you the extent of wear on the chain.

Review this video to find out how to use the CC-4 chain checker tool to check a worn mountain bike chain.

When To Replace A Worn Mountain Bike Chain

Replacing A Worn Mountain Bike Chain
Replacing A Worn Mountain Bike Chain

Now you know the different methods to look for the signs of a worn mountain bike chain.

But when do you have to actually replace a worn MTB chain?

I would say, try and immediately replace it after you notice the signs of wear.

This means, for an 11 or 12-speed mountain bike chain, you can replace it when it reaches .5 percentage wear, and for mountain bike chains with 10 or fewer gears, a .75 mark percentage of wear would be ideal to consider a replacement.

If your mountain bike chain is single-speed or if you ride a two-sprocket bike, consider replacing your MTB chain when it reaches the 1% mark.

This is because, replacing a chain is much cheaper than replacing the whole drivetrain.

The drivetrain components are more susceptible to wear and damage when you continue to ride with a worn mountain bike chain.

Key Factors About Durability Of Mountain Bike Chain

Several factors come into play while determining the durability of your bike chain.

Typically, 2000 miles of traveling is ideal to replace your chain.

However, proper maintenance and timely chain oiling will help you increase the longevity of your mountain bike chain.

It is ideal to clean your mountain bike chain after every ride, and applying lube as and when required.

Different types of lubes, such as dry lube, wet lube, chain wax, etc. are available in the market, and you have to choose the one that best suits your riding environment and your mountain bike.

8 FAQs About Worn Mountain Bike Chain

1. How do I know if my MTB cassette is worn out?

When you notice the signs of a worn mountain bike chain, you must check whether the cassette has started showing the signs of wearing too.

This is because a worn-out chain can easily lead to the wearing of the cassette.

Typically, a worn-out cassette would cause poor shifting and chain skipping.

The delayed symptoms would be the physical changes that you see on the teeth of the cassette.

The teeth of the cassette become more pointy due to the wearing process.

2. How do you check chain stretch?

When the bicycle chain wears, it elongates, causing an impression of stretch. This phenomenon is called chain stretch.

To check chain stretch, you can use a metal ruler or a chain tool.

With the metal ruler, you can mark one end, placing it at the exact center of a rivet. Then count 24 rivets, and if it falls at the 12” mark on the ruler, your chain is intact.

When there is a chain stretch, the 24th rivet would surpass the 12” mark.

You can also use chain checker tools, as mentioned in the article above, to determine chain stretch.

3. What happens when the bike chain is stretched?

The mountain bike chain stretches when the area where the chain link comes in contact with the nuts, and the nut themselves wears out, resulting in a loose (elongating) of the chain.

A stretched bike chain can cause the following issues:

  • Jumping Gears: When the MTB chain stretches, it does not align well with the cassette cogs. This leads to jumping gears, which could be really annoying particularly when you are climbing or putting the power down.
  • Squeaking Sound: You may have to bear the squeaking sound created by stretched chain.
  • Damage to Drivetrain: Riding your mountain bike with stretched chain, will lead to the wearing of other drivetrain parts. The teeth of the cassette and the chainrings will get easily damaged when the chain tension is not right.

Checking the chain slack frequently, and adjusting it or replacing the chain when needed, will help prevent the issues discussed above.

4. How do I check my bike’s chain slack?

It is important to check your mountain bike chain slack once in a while to make sure that it has the right tension.

A simple method to check chain slack is to look at the chain from the side with your eyes in level with it.

If there is too much slack, you will find that the chain sags close to or below the chainstays, and it hangs between the chainring and rear cogs.

When you pedal, the chain might skip, or may have trouble shifting gears.

5. How tight should the MTB chain be?

Ideally, there should be only a .5-inch slack in the chain on a single-speed MTB.

While too much slack is not recommended, you must make sure that the chain is not too tight as well.

However, for a multi-speed mountain bike, lack of slack should not bother you, as the chain is tightened faultlessly with the help of a derailleur spring.

6. How much play should a bike chain have?

A mountain bike chain should ideally have half-inch play.

7. What is MTB chain slap?

Ever heard a slapping sound while biking over rough terrains?

If it is caused due to the chain hitting against the chainstays, it is called a chain slap.

8. How do you silence a chain slap on a mountain bike?

Some solutions to silence a chain slap are as follows:

  • Wrap an old tube or a foam guard on your chainstay.
  • Shift to your higher gear in the front and a lower gear in the back as you descend, in order to tighten the chain and reduce the chain slap.
  • A more expensive solution would be to get a type 2 derailleur, with a 10- speed drivetrain.

That Is All For Now!

I hope you are now equipped with all the information required in understanding the signs of a worn mountain bike chain.

P.S. If you found this content piece helpful, do review our similar resource on how to break, remove, clean and lube your mountain bike chain in the best way possible.

Also check our insights about worn MTB chainring.

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Team Biking KnowHow

Rohan runs Biking KnowHow along with his team. Rohan has been a mountain biker since 2005. His mission is to simplify mountain biking for everyone. All Biking KnowHow content piece is thoroughly fact-checked. Our content is backed up with leading research and inputs from expert cyclists.