Why Does My BMX Bike Chain Keep Slipping? (6 Reasons)

Riding a BMX bike can be an exhilarating experience, but it can also be frustrating when encountering problems like a slipping chain. 

This issue can disrupt your momentum and cause accidents, making addressing the problem as soon as possible essential. 

A BMX chain slipping is common among riders. It can occur for various reasons, ranging from a worn-out chain and sprocket to improper tension and alignment of the chain. A slipping chain not only affects the performance of your bike but also poses a safety risk to you. 

This article will explore why a BMX bike chain slips continuously and provide solutions to help you get back on track.

We will also help you discover your BMX bike’s suitable chain and sprocket size.

Six Reasons Why Your BMX Chain Keeps Slipping and How to Fix?

Riding a BMX bike can be thrilling, but nothing kills the mood faster than a chain that keeps slipping. It can be frustrating and dangerous, especially when performing stunts or tricks. 

Here are seven common reasons why your BMX chain keeps slipping and how to fix them:

#1. Worn or Stretched Chain: 

Over time, the links in your chain can wear down or become stretched, causing it to slip under pressure. 

To fix a worn chain, you will need to replace the chain entirely.

#2. Worn Chainring Teeth:

The teeth on your chainring can also wear down over time, causing the chain to slip when pedaling. To fix the chainring teeth, you will need to replace the chainring.

#3. Worn Cog Teeth:

Similarly, the teeth on your rear cog can wear down over time and cause the chain to slip. You will need to replace the affected cog or the entire cassette.

#4. Loose Chain Tension:

If your chain tension is too loose, it causes your chain to slip when you pedal hard. Adjust the tension by moving the rear wheel back or forward slightly.

#5. Bent or Misaligned Chainring:

A bent or misaligned chainring can cause slipping chains when pedaling. 

To fix the bent or misaligned chainring, you will need to straighten or replace the chainring.

#6. Worn Jockey Wheels:

The jockey wheels on your rear derailleur can wear down over time and cause the chain to slip. You should replace the jockey wheels to fix the slipping problem.

Why Does Your BMX Chain Slip When You Pedal Hard?

BMX chains can slip when you pedal hard for several reasons. One of the most common reasons is a loose or worn chain. 

If the chain is not tight enough or is stretched out, it can jump off the teeth of the gears, causing the chain to slip. 

Another reason could be a worn cassette or chainring. Over time, the teeth on the cassette or chainring can become worn down, making it difficult for the chain to grip properly.

Additionally, a dirty or improperly lubricated chain can cause slipping, preventing the chain from properly gripping the gears.

Finally, a misaligned derailleur can also cause the chain to slip. If the derailleur is not adjusted correctly, it can cause the chain to shift too quickly or not shift at all, causing it to slip.

When you pedal hard on your BMX bike, the chain may slip or jump off the chainring or cassette.  This loss of grip will cause a sudden loss of power and potentially lead to a crash. 

There are several reasons why this might happen:

#1. Worn or Stretched Chain:

Over time, the links in your chain can stretch and become worn, causing them not to grip the chainring or cassette properly. 

The solution is to replace the chain with a new one.

#2. Worn Chainring or Cassette:

The teeth on the chainring or cassette can also become worn or bent, causing the chain to slip. 

If this is the case, you may need to replace the affected component.

#3. Loose Chain Tension:

If your chain tension is too loose, it may slip off the chainring or cassette when you pedal hard. Adjusting the tension using the rear derailleur or chain tensioner can help.

#4. Bent or Damaged Derailleur Hanger:

If your derailleur hanger is bent or faulty, it can cause the derailleur to shift improperly and lead to chain slipping. 

You may need to replace the hanger or straighten it.

#5. Misaligned Derailleur:

If your derailleur is not aligned correctly, it can cause your chain to slip off the chainring or cassette. Adjusting the derailleur alignment can fix this issue.

#6. Dirty or Worn Jockey Wheels:

The jockey wheels on your rear derailleur can become dirty or worn, causing the chain to slip. Cleaning or replacing the jockey wheels would be helpful.

#7. Chain Lubrication:

If you do not lubricate your chain properly, it can become stiff and prone to slipping. Regularly lubricating your chain with bike-specific lubricant can prevent this issue.

Diagnosing and fixing the problem is crucial if you are experiencing chain slipping while pedaling hard on your BMX bike. 

Taking immediate action will help you to prevent accidents or further damage to your bike.

BMX Chain Keeps Jumping Off the Sprocket (Reasons and Solution)

BMX chain jumping off the sprocket is a common problem among BMX riders. It can be frustrating and even dangerous if it happens while you are riding. 

There are several reasons why your BMX chain might keep jumping off the sprocket, and each one requires a different solution. 

Here are some of the most common reasons your BMX chain might keep jumping off the sprocket:

#1. Loose Chain Tension:

A loose chain can cause the chain to jump off the sprocket when you pedal hard. To fix this issue, you need to adjust the chain tension by adding or removing links.

#2. Worn Sprocket Teeth:

Over time, the teeth on your sprocket can become worn and rounded, making it difficult for the chain to grip them properly. 

You need to replace the sprocket to fix this issue.

#3. Bent Chainring or Sprocket:

A bent chainring or sprocket can cause the chain to jump off the sprocket. You need to replace the chainring or sprocket to fix this issue.

#4. Dirty or Worn Chain:

A dirty or worn chain can cause your chain to slip off the sprocket. You need to clean or replace the chain to fix this issue.

#5. Loose or Worn Crank Bolts:

Loose or worn crank bolts can cause the chainring to wobble, which can cause the chain to jump off the sprocket. 

Tighten or replace the crank bolts to fix this issue.

#6. Misaligned Chain:

If the chain is not aligned correctly with the sprocket, it can cause it to jump off. You need to adjust the chain alignment to fix this issue.

What Is the Right Chain and Sprocket Size for Your BMX?

The suitable chain and sprocket size for your BMX depends on several factors, including your riding style, skill level, and personal preferences. 

However, a common sprocket size for BMX bikes is 25T, while chain sizes can vary between 1/8″ and 3/32″. 

Considering the compatibility between the sprocket and chain, gear ratio and tooth count are essential. 

Choosing the proper chain and sprocket size is vital for the overall performance of your BMX bike. 

The chain and sprocket work together to transfer the power from your pedals to the rear wheel.

Therefore, it is crucial to have the right size to ensure your bike runs smoothly and efficiently. 

Here are some key factors to consider when choosing the suitable chain and sprocket size for your BMX.

#1. Gear Ratio 

A higher gear ratio means that the bike will move faster but requires more effort to pedal. 

Conversely, a lower gear ratio makes pedaling easier, but you won’t go as fast. The right gear ratio depends on your riding style and the type of terrain you’ll be riding on.

#2. Chain Width 

BMX chains come in different widths, typically from 1/8-inch to 3/32-inch. The wider chains are more robust and more durable but also heavier. 

The narrower chains are lighter and better for racing but may need to be stronger.

#3. Sprocket Size

BMX sprockets come in various sizes, ranging from 25 to 33 teeth. Smaller sprockets are better for acceleration and tricks, while larger sprockets are better for speed and smooth pedaling.

Here’s a table showing different BMX sprocket sizes and their differences.

Sprocket Size	Description
25T	A smaller sprocket size with quicker acceleration but lower speed and power
28T	A mid-range sprocket size suitable for all-around riding
30T	A larger sprocket size prioritizes top speed and power
33T	A huge sprocket size that maximizes power and speed.
25-9T	A common ratio used in BMX, with a small sprocket and large rear cog for quick acceleration and power.

What to Consider Before Purchasing the Right Sprocket and Chain Size for Your BMX Bike

When it comes to purchasing the right sprocket and chain size for your BMX, there are a few important factors to consider to ensure you make the right choice. Below are some of them;

#1. Frame Geometry 

The first thing to consider is the geometry of your BMX frame. This includes the chainstay length, bottom bracket height, and dropout spacing. 

Different frame geometries will require different chain lengths and sprocket sizes.

#2. Riding Style 

Your riding style and preferences can also affect the chain and sprocket size you choose. 

If you primarily ride street or park, you may want a smaller sprocket and shorter chain for better clearance and responsiveness. 

On the other hand, if you ride dirt or race, a larger sprocket and longer chain may be more suitable for added power and efficiency.

#3. Compatibility 

It’s important to ensure that the chain and sprocket you choose are compatible with each other and the rest of your drivetrain components. 

Check the manufacturer’s specifications and recommendations before making a purchase.

#4. Budget 

Finally, consider your budget when choosing a chain and sprocket. 

While higher-end components may offer better performance and durability, they may also come with a higher price tag.

Considering these factors can help you make an informed decision when choosing the right chain and sprocket size for your BMX. 

It’s also a good idea to consult a knowledgeable bike mechanic or salesperson if you have any questions or concerns.