Learn Why Does My Bike Chain Keep Slipping & How to Fix

Learning Why Your Bike Chain Keeps Slipping & How to Fix

Does your bike chain keep slipping when you pedal hard? Does it feel like the chain is skipping gears or just sliding over the teeth instead of grabbing them? Why does my bike chain keep slipping? This usually happens because parts of your bike’s gear system are worn out or not set up right. A worn bike chain, worn-out gears on the back wheel (cassette wear) or front (chainring wear), or problems with the part that moves the chain (derailleur adjustment or a bent derailleur hanger) are common reasons.

When your bike chain slips, it can feel scary and even dangerous. It means the chain is not staying firmly on the teeth of the gears. Instead, it jumps, skips, or slides. This often happens when you put a lot of power into the pedals, like when riding uphill or speeding up. Let’s look at why this happens and what you can do to make your bike work right again.

Why Does My Bike Chain Keep Slipping
Image Source: i.ytimg.com

Finding Out Why Your Chain Slips

Many different things can cause a bike chain to slip. It’s like a puzzle. You need to check different parts of your bike to find the one that is causing the problem. Most often, the problem is with the parts that make up your bike’s drivetrain. This is the system that sends power from your legs to the back wheel. It includes the pedals, crank arms, chainrings, chain, cassette (the gears on the back wheel), and the derailleurs (the parts that move the chain).

Seeing the Signs of Trouble

Before we dive into fixing things, let’s talk about what slipping feels like.

A sudden lurch: You are pedaling along, and suddenly, the pedals move forward a little without moving the back wheel. It feels like your feet slipped off the pedals for a second.
Noise: You might hear a loud clunking or grinding sound when it happens.
Slipping under pressure: It often only happens when you are pedaling hard, like going up a hill.
Bike chain skipping gears: Sometimes, it’s not just a slip, but the chain jumps to a different gear on its own. This is also a type of bicycle gears slipping.
Chain jumping off: In bad cases, the chain might even jump right off the chainrings or cassette completely.

If you feel or hear these things, your chain is likely slipping. Now, let’s find out why.

Looking At the Main Reasons

Most times, a slipping chain is a sign of wear and tear. Bike parts don’t last forever. The chain and gears wear out over time from use.

worn bike chain

The most common reason for a slipping chain is a worn bike chain. A chain is made of many links. Each link has pins and plates. Over time, these pins and plates rub against each other. This causes the holes in the plates to become slightly larger. This makes the chain longer than it was when it was new. People call this “chain stretch,” but it’s really wear in the joints.

When a chain gets longer, the distance between the pins is no longer the same as the distance between the teeth on the gears. The chain doesn’t fit the gear teeth well anymore. It starts to ride up on the teeth under pressure instead of sitting down snugly between them. This is what causes the slip.

How to Check for a worn bike chain:

You can check your chain for wear with a special tool called a chain checker. This small tool measures the distance between the links.

A common type of chain checker has two ends. You put one end into a link. If the other end drops all the way down into a link at the other side, the chain is worn.
Chain checkers usually have marks for 0.5% and 0.75% wear (or 1% for some types of chains).
- For 9-speed or more gears, replace the chain when it reaches 0.75% wear.
- For 8-speed or fewer gears, replace when it reaches 1% wear.
Replacing the chain at 0.75% wear on a 9-speed or higher system helps save your cassette and chainrings from wearing out too fast.

You can also check wear with a ruler or tape measure.

Measure 12 full links (from the center of one pin to the center of the 13th pin).
A new chain should measure exactly 12 inches.
If it measures more than 12 and 1/16 inches (about 152.4 mm becoming 154 mm), it is worn and should be replaced.
If it measures more than 12 and 1/8 inches (about 155.5 mm), it is very worn.

A worn bike chain is the most likely culprit, especially if you haven’t changed your chain in a long time or ride often.

cassette wear

The cassette is the set of gears on your back wheel. The chain links grab onto the teeth of the cassette gears. When a worn bike chain is used for a long time, it starts to wear down the teeth on the cassette.

Worn cassette teeth don’t have the same shape as new ones. They can become hooked, pointed, or look like shark fins. When the chain tries to grab these worn teeth, it can’t get a good hold, especially under power. This causes the chain to skip over the teeth.

Signs of cassette wear:

Look at the teeth on the gears of your cassette. Do they look pointy or hooked, especially on the gears you use most often? New teeth are more blunt and evenly shaped.
Does the slipping only happen on certain gears? The most used gears (often the middle gears or the smaller ones) wear out faster.
Does a brand new chain slip on your old cassette? If you replace a worn bike chain but still have slipping, it is very likely that your cassette is also worn and needs to be replaced. A worn cassette cannot hold a new, correctly sized chain.

Replacing a worn bike chain regularly helps your cassette last longer. But if your cassette is already worn from a old, worn chain, you will need to replace both the chain and the cassette to fix the slipping.

chainring wear

The chainrings are the gears attached to your crank arms, by your pedals. Just like the cassette, the chain wraps around the chainring teeth. And just like the cassette, chainrings can wear out, especially if you use a worn bike chain for a long time.

Worn chainring teeth can also become hooked or look like shark fins. When the chain tries to grab a worn chainring, it can slip, especially when you shift to that chainring or pedal hard.

Signs of chainring wear:

Look at the teeth on your chainrings. Do they look pointy or hooked, especially on the chainring you use the most? New teeth are more blunt.
Sometimes, the wear is hard to see with just your eyes.
Slipping on the front chainrings is less common than on the cassette. But it can happen. If you have replaced your chain and cassette and still have slipping on the front, the chainrings might be the issue.
If the chainring teeth look very bad, almost like waves or saw blades, they are definitely worn out.

It’s less common to need to replace chainrings just because of slipping compared to chains and cassettes. But if they are very worn, they will cause problems.

Everything is Worn Together

Often, if your chain is very worn, your cassette and chainrings will also be worn, at least on the gears you use most. If you use a worn bike chain for a long time, the whole system wears together.

If you replace just the worn bike chain but keep the worn cassette and chainrings, the new chain won’t mesh well with the old gears. The new chain will likely slip on the worn gears.
If you replace just the cassette but keep the worn chain and chainrings, the worn chain will quickly wear down the new cassette teeth, and it will still slip on the old chainrings.

This is why it is often best to replace the chain and cassette at the same time if the old chain was ridden while badly worn. Sometimes, even the chainrings need replacing too, especially if they are clearly worn. This is a key part of how to fix bike chain slipping properly when wear is the issue.

Looking At Adjustment Problems

Sometimes, the parts are not worn out, but they are not set up correctly. The derailleurs are the parts that move the chain from one gear to another. If they are not adjusted right, the chain might not sit squarely on the gear teeth. It might try to jump to another gear, causing bicycle gears slipping.

derailleur adjustment

Your bike has a front derailleur (for the chainrings) and a rear derailleur (for the cassette). These are controlled by cables connected to your shifters. The derailleurs need to be lined up just right with the gears.

Rear Derailleur: This is the most common place for adjustment problems causing slipping.
- Cable Tension: If the cable tension is wrong, the derailleur might not pull or release the cable enough. This means the derailleur cage might sit slightly off from the center of the gear you are in. The chain then sits on the gear at an angle, making it easier to slip, especially when pedaling hard.
- Limit Screws: These screws stop the derailleur from moving too far inwards or outwards. If they are set wrong, the chain can fall off the smallest or largest gear, or the derailleur can rub against the wheel spokes or frame. While not direct slipping on a gear, it’s a major chain control issue.
- B-Tension: This adjustment controls how close the upper pulley of the rear derailleur is to the cassette gears. If it’s too far away, shifting can be slow, and the chain wrap on the gear teeth might be poor, which can contribute to slipping.

How to spot bad rear derailleur adjustment:

The chain makes noise like it’s trying to shift but doesn’t.
The chain slips or skips only in certain gears.
The chain falls off the gears at the highest or lowest points.
Shifting feels slow or doesn’t happen cleanly. This can feel like bike chain skipping gears.
Front Derailleur: This derailleur moves the chain between the chainrings.
- Cable Tension: Wrong tension can cause the chain to rub on the derailleur cage.
- Limit Screws: These stop the chain from falling off the inner or outer chainring. If wrong, the chain can jump off the front. This is a common cause of the bike chain jumping off the front gears.
- Height and Angle: The derailleur needs to be set at the right height and angle above the largest chainring. If it’s too high, too low, or twisted, it won’t shift well and can cause the chain to rub or jump off.

How to spot bad front derailleur adjustment:

The chain rubs on the derailleur cage in certain gear combinations (e.g., large front ring and large back gear, or small front ring and small back gear).
The chain jumps off the inner or outer chainring. This is a clear sign of the bike chain jumping off.
Shifting between chainrings is difficult or the chain gets stuck.

Adjusting derailleurs takes a bit of practice. You usually need to turn adjustment barrels on the shifter or derailleur to change cable tension, and turn screws (limit screws and B-tension screw) to set the range of motion and pulley distance. Sometimes, the whole derailleur needs to be repositioned on the frame.

bent derailleur hanger symptoms

A bent derailleur hanger is a small piece of metal that connects your rear derailleur to the bike frame. Its job is important: it holds the derailleur in the correct position so that the derailleur pulleys are lined up perfectly with each gear on the cassette.

Derailleur hangers are designed to bend or break in a crash or if the bike falls over. This saves your frame or derailleur from damage. But even a small bend can cause big problems.

If the derailleur hanger is bent, the rear derailleur will not hang straight down. It will be angled inwards or outwards. This means the derailleur pulleys, which guide the chain onto the cassette, won’t line up correctly with the gears.

bent derailleur hanger symptoms:

Shifting problems: Shifting will be poor, slow, or jumpy, especially in certain gears. It might shift fine on one end of the cassette but not the other.
Bike chain skipping gears: The chain will likely skip on some gears because the derailleur is pushing it slightly towards an neighbor gear, preventing it from sitting correctly on the intended gear.
Constant adjustment needed: You might keep trying to adjust the rear derailleur cable tension, but you can never get it to shift smoothly across all the gears. This is a classic sign that the hanger is bent, not just the adjustment.
Noise: The chain might rub on the side of a cassette gear because the derailleur is not aligned.
Chain falling off: In bad cases, the bent hanger can cause the chain to try and shift off the cassette completely, especially towards the spokes.

A bent derailleur hanger is a very common reason for stubborn rear shifting problems and chain slipping that can’t be fixed by simple derailleur adjustment. You can often see if a hanger is bent by looking at the rear derailleur from directly behind the bike. It should hang straight down. If it looks angled, the hanger is likely bent. Fixing this requires a special tool called a derailleur hanger alignment tool to bend it back into shape or replace it if it’s broken or can’t be straightened.

stiff link bike chain

Sometimes, the chain itself is the problem, even if it’s not worn out yet. A stiff link bike chain is a link that doesn’t bend and move freely like the others. The pins and plates in that one link are stuck or tight.

What causes a stiff link:

Damage: The chain might have been hit, causing a pin to be pushed in too far or the plates to be twisted.
Bad installation: If the chain was joined using a pin or quick link, and the pin wasn’t pushed in correctly or the quick link wasn’t fully seated, it can create a stiff spot.
Dirt and rust: Extreme dirt or rust can seize up a link.

stiff link bike chain symptoms:

When you pedal slowly or move the chain by hand, you will see one link that doesn’t bend smoothly as it goes around the chainrings, cassette, or derailleur pulleys. It might stick out or jerk as it passes through the derailleur.
The chain might jump or hesitate as the stiff link goes through the rear derailleur. This can cause a brief slip or jerky feeling.
You might hear a clicking sound every time the stiff link passes a pulley or gear.
Shifting can be jumpy or unreliable.

A stiff link bike chain interferes with the smooth flow of the chain through the system. The derailleur pulleys can’t tension the chain correctly, and the chain can’t sit perfectly on the gear teeth at that spot, causing a slip or skip.

Other Less Common Reasons

Dirty or Dry Chain: A chain that is very dirty, covered in grime, or completely dry without lube can’t move smoothly. The friction can cause it to stick and release quickly, feeling like a slip. Clean and lube your chain often!
Loose Cassette: The cassette should be tightly locked onto the rear wheel hub. If it’s loose, the whole set of gears can wobble, leading to poor shifting and slipping. Check that the cassette lockring is tight.
Loose Chainrings: The chainrings are bolted to the crank arm. If these bolts are loose, the chainrings can wobble, causing the chain to slip, especially under hard pedaling. Check that the chainring bolts are tight.
Wrong Chain Type: Using a chain designed for a different number of gears (e.g., a 9-speed chain on an 11-speed system) can cause major shifting and slipping issues because the width is different. Always use a chain meant for your bike’s drivetrain speed.
Low Chain Tension (Single Speed or Older Bikes): On bikes without derailleurs (like single speeds or some older bikes), the chain needs to be just tight enough. If it’s too loose, it can jump off the teeth. This is less common with modern geared bikes where the derailleur keeps the chain tight.

Figuring Out What’s Wrong

Now that we know the possible causes, let’s figure out which one is affecting your bike. This is like being a bike detective!

Here’s a simple process to check things:

Step 1: Check Your Chain

This is the easiest and most common cause.

Visual Check: Look at your chain. Is it very dirty or rusty? Is there any obvious damage to a link?
Stiff Link Check: Lift the back wheel and pedal slowly with your hand. Watch the chain as it goes through the rear derailleur pulleys. Does any link hesitate or stick out? This would be a stiff link bike chain. Try wiggling it gently with your fingers to see if it frees up.
Wear Check: Use a chain checker tool or a ruler as described earlier. Is the chain worn past its limit (0.5% or 0.75%/1% depending on your number of gears)?

Table 1: Quick Chain Check

What to Check	How to Check It	What It Means if True
Dirt/Rust	Look at it. Is it gunky or orange?	Needs cleaning and lube. Might cause poor running/slips.
Stiff Links	Pedal slowly backwards, watch chain passing pulleys.	Stiff link bike chain is likely cause. Needs fixing.
Wear (using tool)	Use a chain checker. Does it drop to 0.75% or more?	Worn bike chain. Replace it. Will likely slip.
Wear (using ruler)	Measure 12 links. Is it > 12 1/16″?	Worn bike chain. Replace it. Will likely slip.

Step 2: Look at Your Cassette

If your chain is worn, look at the cassette. Even if the chain isn’t badly worn, the cassette could be the issue if it’s very old and has seen many chains.

Visual Check: Look at the teeth on the cassette gears, especially the ones you use most. Do they look pointy, hooked, or like shark fins? Compare them to the teeth on the largest cog (which is used less often and might look newer).
Test with New Chain (if possible): If you put a new chain on your bike and it immediately slips on the old cassette, the cassette is definitely worn out.

Table 2: Quick Cassette Check

What to Check	How to Check It	What It Means if True
Tooth Shape	Look at teeth, especially middle/small gears.	Pointy/hooked teeth mean cassette wear.
Slipping with New Chain	Install new chain. Does it slip on old cassette?	Cassette wear is very likely the cause. Replace it.
Slipping only on some gears	Note if slipping only happens on certain cogs.	Indicates wear on those specific cogs (cassette wear).

Step 3: Examine Your Chainrings

Chainrings wear less often than chains and cassettes but check them too.

Visual Check: Look at the teeth on your front chainrings, especially the one you use most. Do they look pointy, hooked, or very thin?
Bike Chain Jumping Off: If the chain regularly jumps off the front chainring (either inwards towards the frame or outwards towards the crank), this could be a chainring problem (like damage or extreme wear), or more likely a front derailleur adjustment problem.

Table 3: Quick Chainring Check

What to Check	How to Check It	What It Means if True
Tooth Shape	Look at teeth, especially main chainring.	Very pointy/hooked/thin teeth mean chainring wear. Consider replacement.
Chain Jumping Off Front	Does the chain regularly fall off the front?	Could be chainring wear, but more likely front derailleur adjustment.

Step 4: Look at Your Derailleurs and Hanger

These affect how the chain lines up with the gears.

Bent Derailleur Hanger: Stand behind your bike and look at the rear derailleur. Does it hang straight down, or is it angled inwards or outwards? Even a slight angle means the hanger is bent. This is a major cause of bike chain skipping gears that can’t be fixed by adjustment alone.
Derailleur Alignment: With the chain on a middle gear in the back, look at the rear derailleur from behind. The two pulleys (the jockey wheel and the tension pulley) should be lined up vertically under the gear on the cassette you are in. If they look off-center, it’s either a bent hanger or adjustment issue.
Derailleur Adjustment: Shift through all your gears, front and back. Does the chain shift cleanly? Does it hesitate? Does it make noise like it’s trying to shift but doesn’t? Does it slip in specific gears? These point to derailleur adjustment needs. Listen for rubbing. If the chain rubs on the front or rear derailleur cage in any normal gear, it needs adjustment.
Cable Check: Look at the gear cables. Are they frayed or rusty? Do they move smoothly? Sticky cables can mess up shifting and cause problems that feel like slipping.

Table 4: Quick Derailleur/Hanger Check

What to Check	How to Check It	What It Means if True
Hanger Straightness	Look from directly behind the bike.	Angled hanger means bent derailleur hanger symptoms are present. Needs straightening or replacement.
Rear Derailleur Alignment	Look from behind, see if pulleys line up with gear.	Poor alignment can be bent hanger or adjustment issue.
Shifting Smoothness	Shift through all gears while pedaling.	Jerky shifting, hesitation, noise means derailleur adjustment needed.
Chain Rubbing (Front)	In different front/back gear combos.	Front derailleur adjustment needed. May cause bike chain jumping off.
Chain Rubbing (Rear)	In different front/back gear combos.	Rear derailleur adjustment needed. May cause bicycle gears slipping.
Cable Condition	Look at cables, feel them move.	Frayed or sticky cables need replacing. Can cause bad shifting/slipping.

Step 5: Check for Stiff Links Again

Sometimes, a stiff link bike chain is hard to spot until you look closely while pedaling slowly.

Lift the back wheel and pedal slowly. Watch how the chain bends. Does any single link seem to hang up or move awkwardly, especially as it passes through the rear derailleur? If yes, you found a stiff link bike chain.

By doing these checks, you should be able to narrow down the cause (or causes!) of your chain slipping.

Making Things Right: How to Fix Bike Chain Slipping

Once you’ve figured out what’s causing the problem, here’s how to fix it. Sometimes it’s one simple fix. Other times, you might need to fix or replace multiple parts.

1. Replace the worn bike chain

If your chain checker or ruler shows your chain is worn, replace it. This is the cheapest and often the first step in how to fix bike chain slipping.

You will need a chain breaker tool to take the old chain off and shorten the new one.
Most new chains come with a quick link or need a special pin to join them.
Make sure you get the right chain for your bike’s speed (e.g., 10-speed chain for a 10-speed cassette).
After putting on a new chain, make sure you don’t have a stiff link bike chain at the spot where you joined it! Pedal backwards and check the link. If it’s stiff, gently wiggle the link side-to-side or use the chain breaker tool to slightly loosen it (be careful not to push the pin too far).

Important: If you put on a new chain and it still slips, especially under pressure, it means your cassette (and maybe chainrings) are too worn to work with the new chain.

2. Replace the worn cassette

If your cassette teeth look worn or if a new chain slips on the old cassette, you need to replace the cassette.

You will need a cassette lockring tool and a chain whip tool to remove the old cassette.
Make sure you get a new cassette with the same number of gears and that is compatible with your hub and derailleur.
Installing a new cassette is pretty straightforward once the old one is off. Make sure it is seated correctly and tighten the lockring firmly.

After replacing the cassette (and usually the chain at the same time if the old chain caused the wear), your slipping should be fixed if worn parts were the only issue.

3. Replace worn chainrings

If your chainrings are visibly worn or you’ve replaced the chain and cassette and still have slipping on the front, you might need new chainrings.

Replacing chainrings involves taking off the crank arm (often requires special tools depending on the crank type) and unbolting the old chainrings.
Chainrings are more expensive than chains and cassettes. Make sure they are the actual problem before replacing them.
Sometimes, it’s cheaper or easier to replace the whole crankset (crank arms and chainrings together) than just the chainrings, depending on the model.

4. Perform Derailleur Adjustment

If your parts look good or you still have issues after replacing worn parts, you need to adjust your derailleurs. This is key to how to fix bike chain slipping related to setup.

Rear Derailleur Adjustment:
- Start with the limit screws (High and Low). These stop the chain from going off the smallest and largest gears. Set the High limit first (stops chain going off the smallest gear), then the Low limit (stops chain going off the largest gear). There are many guides online and on video showing exactly how to do this.
- Adjust cable tension. This is usually done with barrel adjusters on the shifter or the rear derailleur. Turn the barrel adjuster tiny amounts (quarter or half turns) while pedaling. Turn counter-clockwise to tighten the cable (helps chain move to larger gears), clockwise to loosen (helps chain move to smaller gears). Adjust until the chain shifts cleanly up and down the cassette without hesitation or noise.
- Adjust B-tension. This screw changes the angle of the derailleur body. Adjust it so the upper pulley wheel is close to the cassette gears but doesn’t touch them in the largest cog (or second largest, depending on manufacturer specs).
Front Derailleur Adjustment:
- Set the height and angle first if it’s loose on the frame. The bottom of the outer cage should be about 1-3 mm above the teeth of the largest chainring. The cage should be parallel to the chainrings.
- Set the Low limit screw. This stops the chain from falling off the smallest chainring inwards.
- Set the High limit screw. This stops the chain from falling off the largest chainring outwards.
- Adjust cable tension. This fine-tunes the movement between chainrings.

Derailleur adjustment takes patience. Make small changes and test them by shifting. If you’re unsure, watching a video guide is very helpful. Or take it to a bike shop.

5. Straighten or Replace Bent Derailleur Hanger

If you spotted a bent derailleur hanger, you need to fix this first before trying to adjust the derailleur.

A bike shop has a special tool (a derailleur hanger alignment tool) to check if it’s straight and to bend it back carefully.
If the hanger is badly bent or breaks when trying to straighten it, you need to replace it. Derailleur hangers are specific to bike frames, so you need to get the correct one for your bike make and model.

Trying to adjust a derailleur on a bent hanger will not work and is a common reason why bicycle gears slipping problems persist after attempts at adjustment. Fixing the hanger is essential.

6. Fix Stiff Link Bike Chain

If you found a stiff link bike chain, try to free it up.

Sometimes, simply wiggling the link side-to-side by hand can free it.
If it’s from a pin pushed too far during installation, use a chain breaker tool to gently push the pin back slightly. Push it just enough so the link becomes free, but not so far that it’s loose or comes out the other side.
If it’s from a quick link not seating right, make sure the link is fully engaged. Sometimes, putting the chain on that link on the top of the largest chainring and pushing down hard on the pedals (while holding the brake!) will pop it into place.
If the stiff link is caused by dirt or rust, cleaning and lubing the chain very well might help free it.

If a stiff link cannot be freed up or the link is damaged, you might need to remove the bad link(s) or replace the chain entirely. Replacing the chain is often best if the stiff link is due to damage.

7. Clean and Lube Your Chain

A dirty or dry chain can cause poor performance and contribute to slipping.

Clean your chain regularly using a degreaser and brush or a chain cleaning tool.
Rinse the chain well.
Let it dry.
Apply a good quality bike chain lubricant. Put one drop on each roller of the chain.
After letting the lube soak in for a few minutes, wipe off the extra lube from the outside of the chain with a rag. Extra lube on the outside just attracts dirt.

A clean and lubed chain runs much smoother and can prevent minor slips caused by sticking links or poor movement.

Keeping Your Drivetrain Healthy

Stopping the slipping problem is great, but you want to prevent it from coming back. Here are simple steps to keep your bike’s gears working well:

Clean and Lube Often: Keep your chain clean and well-lubed. This is the easiest way to make your drivetrain last longer and run smoothly. Clean it after riding in wet or dirty conditions, or regularly based on how much you ride.
Check Your Chain Wear: Use a chain checker tool every few months, depending on how much you ride. Replacing a worn bike chain before it wears out your cassette and chainrings saves you money in the long run.
Shift Smart: Try not to shift under heavy pedaling load, especially in the front. Ease up on the pedals just as you shift for smoother changes. Avoid using extreme gear combinations (like the big chainring in front and the biggest cog in the back at the same time, or the small chainring in front and the smallest cog in the back). These “cross-chained” gears put extra stress on the chain and cause faster wear.
Listen to Your Bike: Pay attention to new noises or how shifting feels. Problems often start small.
Regular Check-ups: If you’re not comfortable doing the checks and fixes yourself, take your bike to a local bike shop for a tune-up once or twice a year. They can spot worn parts or adjustment issues before they become major problems.

Summing It Up

Bike chain slipping is a common problem, but it can almost always be fixed. The main culprits are usually a worn bike chain, worn cassette wear, chainring wear, or incorrect derailleur adjustment, including a bent derailleur hanger.

By carefully checking your chain, cassette, chainrings, and derailleurs, you can find out what is causing the slip. Then, you can take the right steps to fix it, whether that means replacing worn parts, adjusting derailleurs, fixing a stiff link bike chain, or straightening a bent derailleur hanger. Keeping your drivetrain clean, lubed, and checking for chain wear often will help prevent the problem from happening again. With a little attention, you can have your bike shifting smoothly and safely once more!

Frequently Asked Questions

Q: Why does my bike chain slip only when I pedal hard?
A: Slipping happens most when you put a lot of force on the chain. If the chain or gear teeth are worn, they can’t hold onto each other well under pressure. This is the most common sign of a worn bike chain or cassette wear.

Q: I just put a new chain on, and now it slips! Why?
A: This is a classic sign that your cassette is worn out. The old, worn chain wore down the teeth on your cassette. A new chain is shorter (not stretched out) and doesn’t fit the worn teeth shape. It will skip over the worn teeth under power. You likely need a new cassette too. Sometimes, even the chainrings might be worn if the old chain was used for a very long time.

Q: Can a dirty chain cause slipping?
A: Yes, a very dirty or dry chain can cause poor performance and feel like slipping. The grime can prevent the links from moving freely, and the lack of lube increases friction, making the chain unable to mesh cleanly with the gear teeth. Cleaning and lubing is the first step for any bike problem!

Q: How often should I replace my bike chain?
A: It depends on how much you ride and in what conditions. The best way to know is to check it regularly with a chain checker tool. Replace it when the tool shows 0.75% wear for 9-speed or higher systems, or 1% wear for 8-speed or lower. For a casual rider, this might be every year or two. For someone who rides every day or in bad weather, it might be every few months.

Q: How can I tell if my derailleur hanger is bent?
A: Stand behind your bike and look at your rear derailleur. It should hang straight down. If it looks angled inwards towards the wheel or outwards, it is likely bent. You can also look down the line of the chain from the rear. If the top pulley isn’t lined up with the cog you are in, it could be a bent hanger. Poor shifting that can’t be fixed with cable adjustment is a major bent derailleur hanger symptom.

Q: My bike chain jumps off the front gear sometimes. What’s wrong?
A: This is usually a problem with your front derailleur adjustment. The limit screws might be set wrong, letting the chain move too far inwards or outwards. The height and angle of the derailleur could also be off. Less commonly, it could be very worn chainrings, but start by checking the front derailleur adjustment. This is a common cause of the bike chain jumping off.

Q: Is “bike chain skipping gears” the same as “bicycle gears slipping”?
A: Yes, these phrases usually mean the same thing. It describes the feeling or sound of the chain not grabbing firmly onto the gear teeth and instead jumping or sliding over them, sometimes causing the chain to jump to a different gear or feel like the pedals are lurching forward.