My Bike Chain keeps Falling off – What do I do?

A bike chain can fall off after a certain period; it’s very normal. However, if a bike chain keeps falling off regularly, it can present several different problems. 

The chain can get caught in the pedals and could lead to a potentially dangerous situation. If the mountain bike chain keeps coming off, it’s a good idea to stop riding your bike for a while and address the issue first. 

A lot of people don’t know what to do when a bike chain falls off. They may think it’s because they didn’t assemble the bike properly or it might be cause there’s too much rust on the chain. It could be any number of reasons. 

That’s why many people that face this issue tend to struggle. They may try one or two fixes and then give up, resigning to take their bike to the local mechanic.

However, with the proper knowledge and tools, there’s no need to visit a bike mechanic. We’ll teach you everything you need to understand why your bike chain keeps falling off and how to deal with the issue! 

What to Do When Your Bike Chain Falls Off? 

Before we take a look at why the bike chain keeps falling off and what you can do to prevent it from happening, it’s essential to discuss what to do immediately after the bike chain falls off. 

When beginner cyclists are riding their road or hybrid bikes, a bike chain falling off can cause trouble. Most new cyclists will make the mistake of continuing to ride even if the bike chain falls off. 

In this situation, continuing to ride is the worst thing that you can do! When the bike chain falls off, the first thing that you should do is to stop riding immediately

Riding the bike with the chain hanging loose can cause several different issues. With the chain hanging loose, there’s a real potential if it gets caught in between the pedals or gets stuck in the tires. The result is a nasty fall that nobody wants to experience. 

Aside from that, the chain is more prone to wear and tear when it’s hanging loose. If you want to save your chain from any additional damage, the best idea is to stop riding the minute it comes loose. 

After that, you can move on to diagnosing what causes the bike chain to keep falling off and how you can fix the issue!

Why does my bike chain keep falling off?

To put it simply, there’s no one specific answer that can explain why your bike chain keeps falling off. There are a myriad of different reasons that could be causing your bike chain to keep falling off and being annoying. 

The only way to determine the main reason behind why your bike chain keeps falling off is to check all the different factors that could contribute. 

That may sound worrying to those that are new to bicycle maintenance. However, there’s no need to panic. Here are the most common factors that contribute to a bike chain that keeps falling off the bike.

Something Loose in the Drivetrain 

One of the most basic principles of repairing any issue in a car is starting with the cheapest component. While cars and bikes are very different, the same principle applies to fixing a bike chain that keeps falling off!

You can start the process by checking whether there are any nuts or bolts loose in the drivetrain. Be careful when you’re testing the parts. Only wiggle them a bit to see if they rattle or move slightly. If you use too much force, then something might break.

Even if you’ve done nothing wrong, there could be some issues in the assembly that might be causing the loose bolts.

How to fix Bike Chain when Something is Loose in the Drivetrain

Before you start working on your repairs, you’ll need to take the bike and hang it upside down. Once the cycle is upside down, it is much easier to examine the chain and access the screws that need tightening. 

While you’re examining the drivetrain for any loose screws, make sure that you check everything gently. By being too firm, you might knock something loose accidentally and create a whole other problem. 

If something is loose in the drivetrain after completing your check, get your wrench and tighten everything. Make sure you don’t make everything too tight and run through all the gears.

Keep your eye on the drivetrain and chain while you’re switching gears. If the chain doesn’t fall off, then you’re good to go! 

Chain Length 

Another reason why the bike chain keeps coming off is the length of the chain. If you recently got a new bike chain, it’s possible for it to be slightly longer than standard.

When changing the bike chain, make sure that you line up the new one perfectly with the old chain. You might need to potentially add or remove chain links if the fitting doesn’t match. 

Alternatively, your bike chain could also stretch with time, making it difficult to use it to measure the length of the new chain. 

If you’ve discarded the old chain or it’s stretched out, you’ll need to put the chain on the bike and then tighten it to get the best possible fit. 

How to fix a Bike that Keeps Falling off due to Chain Length

To address the issue, you’re going to need to invest in a chain splitter. A chain splitter is a tool that allows you to adjust the length of a chain by adding or removing links. Once you have this tool, you can stop a bike chain that keeps falling off. 

The problem usually arises when the cyclist buys a new chain, and it’s too long. When the chain is too long, it won’t fit properly and will keep falling off a bike. That’s where the chain splitter comes into the rescue and lets you remove links from the chain to decrease the length. 

If your old bike chain fits perfectly, then you can use it to check if the length of the new chain is appropriate. However, you’ll be able to manage without the old chain. Just adjust the length of the new chain until it doesn’t leave a lot of slack. 

Chain Health 

Any machine or component that sees regular use will deteriorate with time due to wear and tear. A bike chain is no different. 

Even if the chain hasn’t received any potential damage and you’ve been doing proper maintenance, it might just be time to replace the part. 

Wear and tear may cause the teeth on your crankset or the chainring to deteriorate. Maybe the chain is in decent condition, and the derailleurs are worn out. 

The best way to stay on top of a bike chain that keeps falling off is regular preventative maintenance. That’ll let you keep an eye on your chain health and be aware of when it’s the right time to get a replacement chain. 

How to Fix a Bike Chain that Keeps Falling off – Chain Health

If your chain health deteriorates to the point where there’s no way to repair the damage, then you’ll need to get a new replacement chain. Make sure that you properly fit the new chain; otherwise, you’ll run into the bike chain keeps falling off again issue. 

In certain situations, it’s possible to repair a bike chain instead. Your best bet to get a bike chain properly repaired is to take it to a bike mechanic. After they repair the chain, make sure you know how to tighten a bike chain properly. Otherwise, you can run into trouble. 

Incorrect Shifting 

One of the most common reasons people experience a bike chain that keeps falling off is incorrect gear shifting. 

The bicycle might be running fine, and there are no issues that you can identify, but the chain keeps coming off. That’s a significant indicator that you’re not shifting gears properly. 

A bicycle with a multi-speed drivetrain has a set number of gears. If you try to go past those gears, it can cause the derailleur to extend itself a little too far and cause the chain to keep falling off. 

Take, for example, a 9-speed bicycle. If you’re in the 9th gear and try to shift into 10th gear for some reason, the derailleur would overextend. When the derailleur extends, it’ll cause the bike chain to keep falling off. 

How to Fix a Bike Chain that Keeps Falling off – Incorrect Shifting 

The easiest way to avoid this situation is to not shift forward when you’re in top gear! It’s entirely possible that you make this mistake at the start when you’re relatively unfamiliar with your bike. However, once you gain more experience, you’ll be able to eliminate incorrect shifting altogether. 

Inaccurate derailleur

Many new cyclists fail to identify when an inaccurate derailleur is why their bike chain keeps falling off. 

The easiest way to identify whether you’re suffering from an inaccurate derailleur is by turning the bike upside down. When the bike’s upside down, spin the pedals and keep an eye on the derailleur as you shift through gears. 

The derailleur needs to be in line with the gear that you select on the bike. If it’s slightly off, then that’s what’s causing the bike chain to fall off!

Most modern multi-speed bikes feature both a front derailleur and a rear derailleur. Luckily, the process for identifying why the bike chain keeps falling off is the same for both derailleurs. 

How to Align Derailleurs Properly 

Align the derailleurs properly, and you won’t have to worry about a bike chain that falls off again! Before you start working on the alignment, it’s a good idea to turn the bike upside down so you can get a better view of everything. 

Once you have the bike upside down, shift the chain into the largest chainring and smallest cog. Then you can loosen the cable clamp bolt. When you reduce the cable clamp bolt, you get to access the high and low adjusters. 

These are typically marked with an H and an L. You should adjust the high-gear screw by tightening it until the jockey pulleys align perfectly with the smallest cog. The chain should move around the cog and pulleys smoothly while turning the pedal.

To ensure that the bike aligns properly with the largest cog, rotate the pedal forward and push the rear derailleur in a manner that causes the chain to shift to the respective cog. 

If the pulleys move the chain beyond the largest cog, screw the lower adjuster inwards until the pulley aligns with the large cog. Once it aligns properly, you can reattach the cable and tighten the clamp to lock everything up!

Clogged Chain 

Another reason why a bike chain keeps falling off is that you’re suffering from a clogged chain. When you ride regularly and are fond of riding on trails, then it’s highly likely that you’ll suffer from a clogged chain. 

It’s essential to clean and oil a bike chain regularly to ensure that dirt and grime don’t build up. The presence of dirt and grime in between the chain components can significantly reduce the overall pedaling efficiency of the bike. 

If you’re riding on bumpy terrain, then it’s even more likely that your bike chain keeps falling off because of dirt and grime clogging the inner parts.

How to fix a chain that keeps falling off due to clogging

The amount of cleaning that you’ll need to do depends on the condition of the chain. If it’s really dirty, then you’re going to need to go through a full cleaning with a degreaser before you apply oil on the chain again. 

If you haven’t done any cleaning on your bike chain before then, there’s no need to worry. To clean the chain properly, you’ll need to take it off the bike. Then get a rag or any sort of dry cloth and apply a little bit of degreaser on the cloth. 

You can then use the cloth to clean the chain effectively. Make sure that you are thorough and pay attention to the individual links. You should get the cloth in there to clean properly!

Alternatively, if you take care of your bike chain regularly, then all you’re going to need to do is a few clean rags and chain oil to clean everything up. 

A Bump or Crash 

It’s prevalent for cyclists who engage in many off-road riding to suffer from a bike chain that keeps coming off. It’s entirely possible for cyclists not to notice the damage a particular bump or crash may have done to the bike. 

How to Fix the Bike Chain in Case of a Crash!

If there’s damage to the body’s frame, you might need to take it to a repair specialist. They can then check if the frame needs some adjustment to help stop a bike chain that keeps falling off!

Wrapping Up 

Now you’re familiar with several reasons behind why your bike chain keeps falling off and have enough information to deal with the issue. While it’s annoying for any cyclist to deal with a bike chain that keeps falling off, it’s something that’s both easily identifiable and repairable. 

So make sure that you keep your bike chain tight and perform regular maintenance. That way, you’ll be able to ride without worrying about the chain falling off the bike!

James Dawson

After learning how to ride a bicycle much later than all the other kids, James Dawson hasn't looked back. The author now actively rides a bicycle as a part of the community cycling group and competes regularly in local competitions. Aside from that, he loves technology and always keeps up to date with the latest cycling tech.