Bike Gears Slipping? Why Chains Slip On Bicycles – and How To Fix It

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reviewed by Rory McAllister
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Any bike ride can be ruined pretty quickly if your bike doesn’t work properly, and one of the most annoying problems is your gears slipping.

Not only does it not feel awful, but gears slipping on bicycles can also be pretty dangerous if you are putting a lot of power down. It’s not an efficient way to ride a bike and can play havoc on your components. 

At BikeTips, we often get asked about bike gears slipping. There are many reasons it can happen on a bike, and a lot of the time, it’s pretty easy to fix.

In this article, were going to be telling you everything you need to know about slipping bike gears by discussing:

  • Why Is It Important To Prevent Your Bike Chain Slipping?
  • 5 Key Causes of Bike Gears Slipping
  • Slipping Gears: Identify The Problem And Learn The Solution
  • 5 Top Tips To Prevent Your Bike Gears Slipping
Bike Gears Slipping: Title Image

Why Is It Important To Prevent Your Bike Chain Slipping?

A bike chain slipping is not good for you or your bike. There are so many reasons why it needs to be resolved as soon as it starts happening. Here’s why:

#1. It’s Dangerous

Although it might sound dramatic, a slipping chain can be quite dangerous.

If you’re climbing out of the saddle or applying a lot of power to the bike and the chain slips, it can knock you off balance and make you fall.

#2. It Damages Components

When a chain slips and it then eventually catches, it damages and wears down other components.

It’s not good for parts such as derailleurs to be jumping around and coming in and out of tension.

#3. It Ruins The Cycling Experience

If you are out trying to enjoy a ride and find your bike gears slipping occasionally, it ruins the experience.

Even if they are not slipping all the time, you’re just waiting for them to, and it takes all the fun away – as well as detracting from your performance.

Close-up of the cassette of a carbon fiber bicycle with gears slipping.

5 Key Causes of Bike Gears Slipping

There are many reasons you will find your bike chain slipping. Unfortunately, it’s not always as simple as just one fix. Here’s what causes chain slip.

#1. Worn Out Components

One of the most important parts of a bike is the drivetrain, and many parts make it up. You have the chain, cassette, chainrings, derailleurs, and more.

If anything here is becoming too worn out, the first thing you will experience is slipping gears. 

#2. Derailleurs In Need of Indexing

Another common cause of gears slipping on a bike is when the derailleurs aren’t indexed properly.

This is where they are not guiding the chain exactly where it needs to be on the cassette or the chainrings, and it slips.

We’ll go into more detail on gear indexing below!

#3. Poor Chain Tension

The chain requires a fair amount of tension and needs to stay tight on the drivetrain. If there’s not enough tension, the chain can slip when you are riding.

#4. Dirty Or Unlubricated Drivetrain

Like any mechanical system, the drivetrain works best when clean and well-lubricated.

If a bike’s drivetrain is not in excellent condition, then it’s just not going to work the way it should. It is not rare that your bike is caked in mud for your gears to slip.

#5. Component Compatibility

One mistake we see people making a lot is mixing components that are not designed to work together.

If you use the wrong speed chain or cassette and it can’t properly function with the rest of the drivetrain, it can be a cause of gears slipping on a bicycle.

A cyclist rides a purple road bike in an aerodynamic position.

Slipping Gears: Identify The Problem And Learn The Solution 

There’s a lot we need to check when it comes to identifying why your gears slip. Here is our guide on what to check and the solution to fix it.

Check The Indexing of the Gears

The first place to start is by checking the indexing of the gears.

This is a common cause of gears slipping on a bicycle. The easiest way to do this is to put the bike in the stand or upside down and change gears all the way up and down the cassette while spinning the pedals. 

If your bike has a front derailleur, repeat this step there. If the gears don’t work as they should, more than likely, this is the cause of the slipping gears. 


It’s pretty common for gears to need indexing. You will get it as components wear down and parts such as cables start to stretch. Learning how to index your gears is a great skill to learn.

On the derailleurs, you will have a small barrel adjuster. We recommend turning this anti-clockwise while running up and doing the gears until it shifts properly as it should.

The components of a bike's drivetrain arranged on a yellow background.

Check For Component Wear

Next, we’re going to check the wear of the components. We are going to need to check the chain, cassette, and chainrings. 


You can use a chain wear indicator tool to test the chain. To learn about the process of testing and replacing a chain, check out our in-depth guide here.

Cassette And Chainrings

To check the cassette and chainrings, we must inspect them visually.

What we’re looking for is a “shark teeth” profile. This is a term to describe when the teeth are worn down to a point they start to look thinner and sharper, perhaps with a slight curve – like a shark’s tooth.

This isn’t a foolproof test, as these components can be worn even when the “shark tooth” profile isn’t obvious (especially on the cassette). If in doubt, check with your local bike store.


If you have any worn-out components, then you will need to replace these with compatible parts.

Check The Chain Tension

Next, we will check the chain tension. We recommend first shifting into the smallest ring on the chainrings (front gears) and the smallest sprocket on the cassette (back gears).

Ensure here that the chain has minimal slack, and that the back of the rear derailleur arm has space to move.

Then, shift the chain into the largest chainring and largest cassette sprocket. We do this to check if the chain is long enough to get there. After done, return the chain to the middle of the cassette.


One way to fix chain tension is to use the B-tension screw. This is typically a small screwdriver fitment or Allen key on the rear derailleur. Screwing this in it will tighten the tension up, helping the chain stay on.

Before adjusting the B-tension screw, ensure you have properly identified it, as accidentally adjusting the high and low-limit screws on your rear derailleur could have damaging consequences when you start to ride again.

If you’re not confident, take the bike to your local bike store, and they’ll be able to help you out.

It’s also possible that the chain itself may be the wrong length. If the chain is too long, removing a couple of links will improve chain tension. If it’s too short, you’ll need to replace the chain with a new one that you cut to the correct length.

Check For A Dirty And Unlubricated Drivetrain

Although it might seem easy to take a glance and look for dirt on the drivetrain, there are better ways to check.

I have often thought my drivetrain is clean and lubricated, but under close inspection, I found loads of hidden dirt and even broken parts. 


If the chain is thoroughly dirty, we recommend removing it and cleaning it with a strong bike degreaser.

Then head to the cassette and chainrings and clean them thoroughly. Finally, turn your attention to the jockey wheels, remove hidden dirt, and ensure the bearings are nice and smooth. 

Put it all back together, add lubrication, and clean off the excess oil using a dry rag. Give it a quick test, and you’re good to go. 

A cyclist rides an orange road bike on a racetrack.

5 Top Tips To Prevent Your Bike Gears Slipping

There’s a lot you can do to stop the gear from starting to slip in the first place. Here are our top tips:

  1. Keep a clean drivetrain with enough lubrication.
  2. Regularly service your bike and change the chain often.
  3. Stay on top of the indexing of your bike gears.
  4. Only use parts from good manufacturers such as Shimano, SRAM, and KMC.
  5. Don’t use parts that are not compatible or designed for your drivetrain.

Now You Know All About Bike Gears Slipping…

Slipping gears can be incredibly annoying and really ruin the cycling experience.

It’s important when they start slipping to get your bike fixed as soon as possible because it will only worsen with time!

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Robbie has traveled the globe as an endurance athlete and bikepacker, breaking world records and competing in international ultra-cycling events such as the BikingMan series and the Transcontinental Race. He's also worked as an ambassador for some of the industry's leading names, including Shimano and Ritchey. If Robbie's not on a bike, he's either fixing them or out walking with his dog!

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