Why Does Mountain Bike Chain Keep Coming Off

It’s inconvenient to have your mountain bike chain fall off while mountain biking. And when it’s not once but multiple times it’s irritating.

Wondering why my mountain bike chain keeps coming off like this? 

When it comes to mountain biking, a properly lubricated chain is key. This component allows you to ride smoothly and with less wear and tear on your gears, which in turn increases your efficiency and speed. 

When the chain is poorly lubricated the chain links will rub against each other. This friction will cause the chain to wear down quickly, which leads to the mountain bike chain coming off.

Poor lubrication can be caused by things like rust or scale buildup on the moving parts of the bicycle, which reduces the amount of oil that is able to reach those parts. Worn-out pulleys, gears, and links can also cause problems with lubrication.

So what can you do to prevent frequent chain drops?

First and foremost follow the chain guide. Make sure the bike is properly lubricated; this will help reduce the amount of friction between the chain links and also keep the gears running smoothly. Second, be sure to replace your chainring regularly if it starts to show signs of wear – usually every 100 miles or so. Finally, inspect your bike’s gear system frequently for any problems that may be related to chain wear. If you notice anything strange, such as difficulty shifting or noisy gears, get your bike checked out by a professional.

What Causes Mountain Bike Chains to Keep Coming Off

What Causes Mountain Bike Chains to Keep Coming Off

There are a few different causes for mountain bike chains that keep coming off, including mechanical issues, chain length, loose chain, chain wear, cable tension, broken chain part, stiff link, bent tooth, incorrect chain size, etc.

The most common is wear and tear. Over time, the teeth on the chain become more worn down which can lead to chain slipping from the gears.

Another reason for chain drop is the chain is too tight, which forces the rear derailleur to work harder and wears down the gears over time. 

Dirt and grit buildup can also cause chain drop. It comes from riding over harsh surfaces (such as gravel) or during rides that involve lots of climbing/descending. 

In addition, if you’re not using lube regularly or your cassette has too much resistance, then it may also slip out of gear.

If this happens while riding at high speeds or downhill riding, it can be really dangerous as you could end up crashing into other riders or obstacles. So, you must take the necessary steps to prevent this from happening. You have to do nothing much. Make sure to check your chain frequently (at least once every 20 miles) and lubricate where needed with an effective mineral oil product.

Why Chain keep coming off the bike when changing gears

Chain retention can be a major problem when it comes to cycling. There are a few potential causes for it, and probably chain slack is causing the chain to keep coming off when changing gears. Chain slack is the gap between the gear and chain, and when it’s too wide, dirt or grit gets caught in it and makes gear shifting difficult and the chain comes off.

Some more factors behind the Chain keeps coming off when changing gears are-

  • Worn chain, narrow wide chainring
  • Defective gears
  • The chainring is too tight or too loose
  • Mismatch in the width of the ring and sprocket
  • The drivetrain is not shifting to the correct gear

Bike Chain Falls Off When Pedaling Hard

There can be many reasons for a bike chain to fall off when you pedal really hard. One of the most common reasons is the chain is loose. You might need to adjust the tensioning of the chain by using a park tool like a bicycle chain tool.

Let’s get to know a few more.

  • Another reason can be the drivetrain is not lubricated well enough. Make sure to properly lubricate it after every 100-mile ride.
  • Sometimes the bike chain falls off when pedaling hard because the sprocket teeth on the rear wheel are worn down and no longer mesh together properly. This results in too much slack in the chainring, which makes it prone to slipping.
  • In addition, when you pedal hard, the bike chain may start to fall off because of the centrifugal force. Use a good quality chainring and tight it properly to prevent this.
  • The bike chain falls off also when pedaling hard when you pedal at a high speed. In this situation, the pedals go up and down quickly which causes the chainring to bounce and fall off

Bike Chain Keeps Falling Off Single-Speed

There could be a few reasons why your bike chain keeps falling off your single speed – improper installation, chain stretch, incorrect tensioning of the chain, broken bike chain, and more. It is important to troubleshoot and fix the issue as soon as possible to prevent it from becoming worse.  

It can happen when there’s a low tension between the chains with a wrong chain line. Then the bike frame can get bent, which in turn causes the chain to fall when riding with a single speed.

A wheel cog can also cause your chains to fall off. And if the rear chains on the rear tire aren’t adjusted tightly or stretched, there’s a high chance you will face chain drop when you’re riding at a single speed.

To keep your mountain bike running smoothly and prevent chain-related issues, be sure to inspect and maintain all the components regularly. Check for chainsuck (leads coming off), excessive wear, or rough edges on cassettes, hubs, and derailleur cages. Replace worn parts as needed. Load the bike properly to avoid flexing and damaging parts.

Why Does My New Bike Chain Keep Coming Off

Why Does My New Bike Chain Keep Coming Off

Usually, with a new bike, you may experience problems with the new chain coming off only when the chain link is not properly installed or the rear axle isn’t tight enough against the rear sprocket or is too tight.

So, when you purchase a new bike, it’s important to have it checked out by an experienced cyclist or mechanic to make sure that the gears, brakes, and component parts are all in working order. If there are any inconsistencies with the bike itself (like a mismatched chain), it will likely need corrective action before you can ride safely.

If your chain isn’t fitting properly because of worn or stretched links, this can cause tension on both sides of the link as you pedal. This tension will eventually pull the chain from its drivetrain bearings (where each end meets) which results in intermittent loss of speed, difficulty in shifting gears, and chain drop.

Quick Fix Bike Chain Keeps Coming Off

The most frustrating and dangerous thing about riding a bike is chain drop.

So, how can we quickly fix the loose bike chain that keeps coming off?

Let us know.

  • One common cause of a bike chain coming off is that the sprockets have become too tight. In that case, adjust the bike chain tension. Still, if it keeps coming off, replace the sprocket.
  • Make sure that the bike’s derailleur is in the correct gear and the chain is not caught on anything. 
  • Double-check all your drivetrain limit screws, and ensure they are secure, nothing has slipped or shifted.
  • The rear cassette is properly positioned in the dropouts.
  • Clean and lubricate the old chain’s pulleys, sprockets, and cogs as needed


I believe now you are all clear about the reasons behind why your mountain bike chain comes off. Keeping the causes and solutions in mind can easily save you money and time. So, we hope our article has eased your problem.

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