Published on:

Why The Bike Chain Keeps Coming Off And How To Fix It Easily

A properly functioning bike chain is like the lifeblood of a smooth and safe ride. It keeps you cruising comfortably and makes cycling a joy. But, you know what’s not fun? When the bike chain keeps coming off. It’s a pesky problem that interrupts your ride and can be dangerous. This article explores why it happens and, most importantly, how to fix it. Let’s dive in!

Suspect Number 1: Dirty Components

Over time, dust, grime, and debris can accumulate on the chain, cassette, jockey wheel, and derailleur—components that are integral for the proper functioning of the bike. As you ride, the open design of these elements makes them susceptible to picking up environmental dirt, especially when you tread on muddy or dusty terrains. Further compounding the problem, the chain lubricant can act as a sticky magnet, attracting and holding onto the dirt. This accumulation not only increases friction but also interferes with the smooth interlocking of the chain with the cassette and derailleur, potentially leading to maladjustments and causing the chain to come off.

Signs Of A Dirty Chain And Cycle Components

Identifying a dirty chain, cassette, jockey wheel, and derailleur can be quite straightforward if you know what to look for.

One of the first signs of a dirty chain is a distinct, gritty sensation when you run your fingers over the chain. You may also notice a significant amount of black residue on your fingers, which is a combination of dirt and old lubricant. 

A noisy chain while pedaling is another common indication of dirt buildup. This unusual sound can be attributed to the increased friction between the chain and the gears due to the accumulated grime.

In terms of the cassette, jockey wheel, and derailleur, the buildup of dirt often manifests as a thick, grimy substance that can be visibly seen. Accumulated dirt may also cause them to become stiff and less responsive, resulting in sluggish gear changes. If your bike starts doing hard shifts or the derailleur doesn’t spring back quickly, it’s time for a thorough clean to restore the smooth functioning of your ride.

How To Clean Your Chain, Cassette, Jockey Wheel, And Derailleur

Cleaning your bike’s chain, cassette, jock wheel, and derailleur is essential for optimal performance and longevity. Follow these steps to give your bike components a thorough cleaning:

  1. Preparation: First, you’ll need a few cleaning tools: a chain cleaning device, bike-specific degreaser, a small brush, and a rag. For a more thorough clean, you might also want to consider a cassette removal tool to reach the inner parts of the cassette.
  2. Initial Cleaning: Start by applying the bike-specific degreaser to the chain, cassette, jockey wheels, and derailleur. Allow it to sit for a few minutes to break down the grime and dirt. 
  3. Deep Cleaning: Next, use the chain cleaning device on the chain. This tool has brushes and rollers inside that deeply clean the chain as you spin it through the device. For the cassette, jockey wheels, and derailleur, use your small brush to scrub the dirt off. If you decided to remove the cassette, this is the time to get in there and give it a good scrub.
  4. Wipe Down: Once you’ve scrubbed all the parts, rinse them off with warm water. After that, use your rag to dry the chain, cassette, jockey wheel, and derailleur, ensuring they’re completely dry to avoid rusting.
  5. Lubrication: Finally, apply a suitable chain lubricant evenly over the chain and lightly on the cassette, jockey wheels, and derailleur. This reduces friction and prevents future dirt accumulation.

Check out this video if you want to know more about how to clean your bike properly.

Suspect Number 2: Loose Or Tight Bike Chain

Bike chain misalignment is another common culprit causing a loose or tight bike chain.

Even a slight diversion can result in chain slippage or over-tightening. Misalignment can typically occur due to regular wear and tear, poor assembly, or after an impact from a fall or collision. 

Signs Of A Loose Or Tight Bike Chain

Identifying a loose or tight bike chain can save you from a potentially hazardous bike ride. Here are the signs to watch out for in each case:

Loose Bike Chain

A loose bike chain can often produce a rattling sound as it bounces around while you ride. You may also notice that the chain appears to sag or droop, especially when the bike is on a stand and the pedals are not under tension. Shifting gears might become unpredictable, as a loose chain does not engage well with the derailleur. In the worst-case scenario, a loose chain could slip off the chainring or cog, interrupting your ride.

Tight Bike Chain

On the flip side, a tight bike chain can make your ride feel stiff and unresponsive. The chain will show little to no sag, even when the bike is stationary and the pedals are not under tension. You might also observe that your bike is harder to pedal than usual, due to increased friction and reduced mechanical efficiency. While shifting gears, a tight chain might resist moving onto the next cog or chainring, resulting in delayed or missed shifts. The excessive tension may also wear down the drivetrain components faster, leading to premature failures.

How To Fix A Loose Or Tight Bike Chain

Fixing a loose or tight bike chain is a fairly straightforward process. You’ll need a few tools like a bike stand, a wrench, and a little patience. Here’s a simple guide:

  1. Inspect the Chain: Start by visually inspecting the chain. If it’s too loose, it may sag and not properly engage with the gears. If it’s too tight, it won’t have any slack and may resist shifting gears.
  2. Adjust the Rear Wheel: Loosen the bolts that hold the rear wheel in place. If the chain is too loose, pull the rear wheel back slightly to tighten it. Conversely, if the chain is too tight, push the rear wheel forward a bit to loosen it.
  3. Check the Chain Tension: Rotate the pedals to move the chain around the entire gear set. Check the tension in multiple places by pressing your fingers against the chain. It should deflect slightly but not sag.
  4. Tighten the Rear Wheel Bolts: Once you’re satisfied with the chain tension, tighten the rear wheel bolts. Make sure the wheel is straight and aligned properly with the bike frame.
  5. Test Ride: Lastly, take your bike for a short ride to test the chain tension. Ensure the gears are shifting smoothly and that the chain is not too loose or tight.

For a more detail, check out our comprehensive article: How to Tighten a Bike Chain in 7 Easy Steps. This will provide you with a more detailed, step-by-step instructions, along with useful images and tips for tightening or loosening your bike chain.

Suspect Number 3: Worn Out Or Damaged Bike Parts

The bike chain, derailleur, or cassette can get damaged in several ways. One common cause is improper maintenance, which includes infrequent cleaning and insufficient lubrication. This can lead to the accumulation of grit and grime that can wear down the metal over time. Excessive tension in the chain can also cause stress on these components, leading to premature wear and potential breakage. 

Another factor is poor handling or rough riding habits, like shifting gears under heavy load or riding on rough terrains without proper bike setup. This can also cause undue strain on the bike chain, derailleur, and cassette, leading to potential damage or failure. 

Exposure to harsh environmental conditions such as extreme cold, heat, or moisture can also negatively impact these components. Moisture, in particular, can cause corrosion if the bike is not dried properly after a wet ride. 

Accidents or impacts—from falling off the bike or collisions—can also lead to immediate, noticeable damage. The derailleur is particularly vulnerable due to its position on the bike, where it can easily get hit or bent.

Signs Of A Damaged Bike Chain, Derailleur Or Cassette

Here are some signs that indicate potential issues with these components:

Damaged Bike Chain

A damaged bike chain can significantly affect your riding experience. Signs of a damaged chain may include:

  • Stiff Links: If a link doesn’t pivot as it passes through the derailleur or around the cassette, it can cause skipping or derailment.
  • Rusted or Corroded Links: Rust and corrosion can add friction, reducing the chain’s overall efficiency.
  • Excessive Wear or ‘Stretch’: Over time, chains elongate due to wear on the bushings and rollers. If your chain skips on the cassette while riding under load or falls off the chainring, it might be stretched.

Damaged Derailleur

The derailleur is a crucial part of your bike’s gear system. Here are a few signs of a potentially damaged derailleur:

  • Difficulty Shifting Gears: If the derailleur is bent or damaged, it can cause the gears to shift erratically or not at all.
  • Visible Damage: Any visible cracks, bends, or broken pieces in the derailleur can indicate damage.
  • Unusual Noises: Grinding, clicking, or squeaking noises from your derailleur during a ride can signify a problem.

Damaged Cassette

The cassette plays a key role in maintaining the speed and accuracy of your gear changes. Signs of a damaged cassette may include:

  • Skipping: If your chain skips over the teeth of the cassette while riding, it can be a sign that the cassette is worn out.
  • Unusual Wear Patterns: Look for uneven or hooked teeth, which can indicate excessive wear.
  • Difficulty Shifting: Difficulty or inability to shift into certain gears can also indicate a problem with the cassette.

What To Do If The Bike Chain, Derailleur, Or Cassette Is Damaged

If you’ve identified damage to your bike chain, derailleur, or cassette, it’s vital to address the issue promptly to ensure a safe and efficient ride. Here are some recommended steps:

Bike Chain:

If you have a damaged bike chain, consider replacing it. Using a chain tool, remove the old chain and measure the new one to ensure a proper fit. Make sure to lubricate the new chain thoroughly before installing it.

Derailleur:

In case of a damaged derailleur, you may need professional help. If the damage is severe (like visible cracks or bends), a replacement might be necessary. For minor issues, a bike shop can often realign or adjust the derailleur.

Cassette:

A damaged cassette can significantly affect your ride. If it’s showing signs of excessive wear or causing gear shifting problems, it’s time to replace it. Removing a cassette requires a specific tool, and installing the new cassette involves careful alignment, so this might be a job for a professional mechanic.

If you’re really into doing everything by yourself, I stumbled upon a bunch of super helpful videos that could be really valuable to you.

How to replace a bike chain:

How to replace a derailleur:

How to replace a cassette:

Suspect Number 4: Misaligned Deralliers 

Derailleurs can become misaligned for various reasons, such as a bent derailleur hanger or wear and tear over time. Improper installation or adjustments can also cause misalignment. This can lead to issues with gear shifting and affect the overall performance of the bike.

Signs Of Misaligned Derailleurs

Here are the most common signs of a misaligned derailleur, besides the chain keeps coming off:

  • Difficulty Shifting Gears: If you find yourself struggling to shift gears smoothly, it could be a sign of a misaligned derailleur. This is especially true if the problem persists even after cleaning and lubricating your drivetrain.
  • Chain Skipping or Jumping: A misaligned derailleur can also cause your chain to skip or jump off the gears. This can be a dangerous issue, as it can cause you to lose control of your bike while riding.
  • Chain Rubbing Against Gears: Another common sign of a misaligned derailleur is when your chain rubs against the front or rear gears while pedaling. This not only creates an annoying noise but also causes unnecessary wear and tear on your drivetrain.
  • Difficulty Braking: If you’re noticing that your brakes are not as responsive as they used to be, it could be due to a misaligned derailleur. A misalignment can cause the brake pads to rub against the rim or disc, affecting their ability to grip and slow down the bike effectively.
  • Pedals Feeling “Off” or “Uneven”: A properly aligned derailleur ensures that the chain moves smoothly between gears, resulting in a smooth and even pedal stroke. However, if your derailleur is misaligned, you may notice that one side of your pedals feels heavier or more difficult to push than the other.
  • Frequent Chain Slips: If you’re experiencing frequent chain slips while riding, it could be a sign of a misaligned derailleur. When the gears are not properly aligned, the chain may struggle to stay in place and can easily slip off the teeth of the gears.
  • Difficulty Shifting Gear: A misaligned derailleur can also affect your ability to shift gears smoothly. This is because the derailleur plays a crucial role in moving

How To Align Rear And Front Derailleurs

Proper alignment of both the front and rear derailleurs is crucial for smooth gear shifting and optimal bike performance. Here’s a simple guide on how you can realign your derailleurs:

Rear Derailleur:

  1. Shift Your Gear to the Lowest Setting: Ensure that the chain is on the smallest chainring at the front and the smallest cog at the back.
  2. Check the Derailleur Alignment: Look at your derailleur from the back. The derailleur pulley should be perfectly vertical with the smallest cog. If not, you need to adjust the derailleur hanger alignment.
  3. Adjust the Hanger Alignment: Use a derailleur hanger alignment tool to make adjustments. You need to align it so that the derailleur pulley is in line with the smallest cog.
  4. Fine-Tuning: After aligning, shift through all the gears to ensure the shifting is smooth. If not, make fine adjustments using the barrel adjuster.

For more information, check out this video:

Front Derailleur:

  1. Shift Into Middle Gear: Start by shifting the chain onto the middle chainring and the middle rear cog.
  2. Check Alignment: The cage of the front derailleur should be parallel to the chain. If it’s not, loosen the derailleur clamp slightly and adjust it until it’s parallel.
  3. Check the Height: The bottom of the derailleur cage should be about 1-3mm above the top of the teeth on the largest chainring. Adjust by loosening the clamp and raising or lowering the derailleur.
  4. Fine-Tuning: Shift through all gears to ensure smooth shifting. If necessary, use the barrel adjuster for small adjustments.

For more information, check out this video:

Suspect Number 5: Loose bolts or screws

Loose bolts or screws in a bike’s drivetrain can result from normal wear and tear, improper installation, or environmental conditions. Vibrations, impacts, and riding on rough terrain can gradually loosen components. Incorrect torque, wrong screws or bolts, and lack of washers can also lead to loosening. Environmental factors like extreme temperatures and corrosion can further contribute.

How to Tighten Loose Bolts

Tightening loose screws or bolts on your bike’s drivetrain is a relatively straightforward task that requires a few basic tools. 

  1. Identify the Loose Screws/Bolts: The first step is to identify any loose screws or bolts. You can do this by visually inspecting your drivetrain for any apparent looseness, or by gently shaking each component and listening for rattles.
  2. Gather Your Tools: Typically, you’ll need a set of Allen keys or a torque wrench, depending on the type of screws or bolts your bike uses. 
  3. Tightening the Screws/Bolts: Apply pressure in a clockwise direction to tighten each screw or bolt. Be careful not to over-tighten them as this could cause damage. For the most accurate results, use a torque wrench and tighten each bolt to the manufacturer’s specifications, if available.
  4. Final Check: Once you’ve tightened all the screws/bolts, give your bike a final inspection to ensure everything is secure. Rotate your pedals and shift through your gears to make sure everything is functioning smoothly.

Remember, if you’re unsure or uncomfortable performing these steps, it’s best to take your bike to a professional mechanic. 

But, If you want to give it a shot yourself, I recommend checking out this video:

FAQ 

How often should I replace my bike’s chain?

The lifespan of a bike chain depends on various factors such as riding style, terrain, and maintenance. On average, a well-maintained chain can last between 2,000 to 3,000 miles. However, it’s always best to regularly check your chain for signs of wear and replace it when necessary.

Can I replace my bike’s cassette by myself?

While it is possible to replace a cassette at home, it does require special tools and precise alignment. It may be best to take your bike to a professional mechanic for this job to ensure proper installation and avoid any potential damage. 

How can I prevent my bike’s bolts and screws from loosening?

Regular maintenance is key to preventing loose bolts and screws on your bike’s drivetrain. Make sure to check and tighten them periodically, especially after rides on rough terrain. Using proper torque and quality components, as well as adding washers where necessary, can also help prevent loosening.  Additionally, storing your bike in a dry and clean environment can help minimize corrosion and extend the lifespan of your bolts and screws. 

What To Do Next

Now that you know the common causes of lousy gear shifting and how to fix ’em, you can confidently troubleshoot any future issues with your bike’s derailleurs. Just remember to regularly do maintenance checks and make necessary adjustments to keep that performance in top shape!

Photo of author

Author

Mate is a passionate bikepacking enthusiast and the founder of this website. He loves exploring new destinations, admiring nature, and engaging in outdoor activities. He strongly believes that healthy living should be environmentally friendly too, which is why he prefers to use bicycles for his transport needs.