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Amountain bike chain skipping under loadis one of the most common issues you may see when you ride your mountain bike.
Unfortunately, this can be dangerous and may affect your overall riding experience.
So it would help if you tried to fix a mountain bike chain that is skipping or jumping gears as soon as you can.
Fixing MTB chain that is skipping gears may sound challenging.
On the contrary, it is simple.
If you identify why your mountain bike chain is skipping gears just follow some immediate steps that we have outlined for you here, you can fix it and go on your next ride.
Lets dig in!
5 Reasons Why Mountain Bike Chain Keeps Skipping Under Load When Pedaling Hard?
There can be many reasons why your mountain bike chain can keep skipping under load.
Below mentioned are 5 common factors that you must keep in mind to fix it.
1. Misaligned Derailleurs:
If you have a new mountain bike, there will be no sign of any damaged drivetrain.
Yet if somehow the hanger bends, it is because of the misalignment of the rear derailleur.
This causes the skipping of the chain.
2. Stretched Chain:
The skipping of the MTB chain can take place due to a stretched chain.
If the chain is elongated and becomes longer than the needed chain length, the tension of the chain reduces.
This can make your MTB chain skip while paddling hard.
3. Damaged Drivetrain:
A damaged drivetrain is one of the most common reasons for causing skipping of the MTB chain.
The chain will not stay on the cog teeth when it becomes too rusty or worn out.
Also, the chain will skip if there are broken teeth on chain rings or cogs.
4. Wrong Chain:
Different types of mountain bikes have different types of chains.
The chain for one group set is different from the other one.
One reason a mountain bike chain skipping under load can be caused if the chain you are using is not much compatible with the derailleurs of your mountain bike.
5. Freewheel Problem:
A mountain bike’s ratchet or freewheel mechanism lets you keep your mountain bike running when you do not paddle.
During clockwise paddling, the rear wheel will rotate.
But when you do not paddle, the freewheel will prevent your mountain bike from stopping.
Sometimes, from the inside, the freewheel will be damaged.
This can cause the hub to fail to transfer energy through the wheel, hence causing an artificial chain skip.
Related: Clipless Vs Flat Pedal Ridding
9 Ways To Fix A Skipping Mountain Bike Chain
Having your mountain bike chain skipping under load can be a real headache.
Yet you can quickly fix it as long as you have the perfect tools and follow some steps.
First, forward pedal your bike to fix the skipping chain of your MTB.
Then turn the barrel adjuster, check your shifter, adjust your cable, and finally, tighten your derailleur screw.
Here are the 9 fast and straightforward steps to follow for fixing a bike chain that will jump between gears.
1. Forward Pedal Your Mountain Bike:
To fix a bike chain skipping, you need to manually forward pedal your mountain bike.
Then shift the MTB chain from the smallest cog to the biggest one on the back and the most prominent front chain ring.
It will let you see how loose or tight your bike chain is and if you require adjusting its tension.
2. Turn your barrel adjuster:
They look the same as serrated knobs.
Barrel adjusters are often considered solutions for cable tension.
They make sure that the guide pulley of the derailleur lines up with the cogs and that every shift gets aligned with every cog.
To solve the shifting problem, you need to turn the barrel clockwise in half-turn increments.
3. Check your mountain bike shifter:
Check your mountain bike shifters by pressing it once.
If you observe that the chain is shifting to the smallest cog of the cassette, then understand that it is tight enough.
If not, then you must require more tension in your chain.
Next, check the shifter to let you know if the chain will move up one gear.
If nothing happens, you must re-adjust your barrel adjuster so that it properly shifts.
4. Adjust your mountain bike cable:
Loose cables may cause your mountain bike chain to jump between gears.
For fixing a skipping chain, you need to add tension to the stretched rear derailleur cable.
Adjust the tension of the rear derailleur cable by first shifting your bike to the smallest gear to release the tension of the chain.
When the cable is loose enough, make use of an Allen wrench to remove the bolt holding the cable.
Next, use your hand to pull the slack to tighten the cable and secure the bolt.
5. Tighten your derailleur screw:
When you fix a jumping mountain bike chain, you must tighten the chain by adjusting the body-angle screw of the derailleur.
You must use a screwdriver and then tighten the screw.
It will add tension to your mountain bike chain.
Thus it will prevent it from skipping and slipping.
6. Measure your chain wear regularly:
If your mountain bike has a worn chain, it may be a reason that the chain will continue to skip gears.
To find out if the bike chain requires replacement, you must measure chain wear using an indicator tool of chain wear.
As an alternative, a ruler or caliper may also be used.
If your mountain bike chain is too worn down, replace it with a new one.
It will sit tighter.
It will prevent the chain from jumping or slipping and will reduce the risks of damaging any drivetrain components.
7. Check Worn Down Cassette:
Ride a bike with any worn cassette can be a common reason why your mountain bike chain keeps skipping under load.
In the case of MTB cassette, often smaller cogs will be worn down more compared to larger ones.
So you must always be alert about the smaller cogs.
Also, if you notice that your mountain bike’s cog teeth got damaged or are uneven, you need to consider replacing the cassette to fix the bike chain to skip.
8. Clean Your Bike Chain Regularly:
Your mountain bike’s chain will jump between gears if it is not adequately lubricated.
If it happens, you must first clean your mountain bike chain.
Use a chain cleaning device and a degreaser. Then add one drop of lubricant to every chain link. It will lubricate it properly.
Related: How Often To Lubricate MTB Chain
9. Align Your Derailleur Hanger:
If your mountain bike’ derailleur hanger gets damaged, there is a risk that the bike chain will begin jumping between gears.
It would help if you use a derailleur hanger alignment gauge to stop this from happening.
Use the derailleur hanger alignment gauge to align the hanger not only horizontally but also vertically.
Doing this regularly will help prevent your mountain bike chain skipping under load problem.
9 Common FAQs About Skipping MTB Chains
1. Why does my mountain bike chain skip when I pedal backward?
Mountain bike chain skips when you pedal backward mostly due to the worn derailleur pulleys.
MTB chain skipping can be caused by derailleur pulleys being either old or mis-alignment.
MTB chain skipping also happens due to derailleur pulleys being bent, or broken teeth on one or more than one cassette cogs.
Moreover, the built-up of grime or dirt in the drivetrain component can cause shifting problems, such as skipping chains.
2. How do you adjust the tension on your mountain bike chain?
Adjust the tension on your mountain bike chain by increases the pressure on your MTB chain and by reversing the direction of the rear tire’s rotation.
You must slowly pull back on the rear tire to adjust this chain tension.
If you move very fast during this process, then the chain can be snapped.
Check the tension of the chain as you pull back and keep on doing it until you get the desired tightness.
You will be able to move the bike chain almost half an inch in either direction.
3. Why does the mountain bike chain keep slapping?
As your MTB keeps running on the stand, it can cause slapping in your mountain bike chain.
It leaves the chain freely hanging, causing it to slap aggressively.
Having no proper tension in your MTB chain, letting it sway upwards and downwards can be one of the main reason for causing chain slapping.
4. Why does a mountain bike chain suddenly slack?
A mountain bike chain can slack easily if the front derailleur is very high or low for some gears.
If your mountain bike comes with a cassette freehub and you do not make use of any lubricant on the clogs, then also it may suddenly slack.
If you use too much force while you pedal or if your rear derailleur hanger is damaged, then your mountain bike chain may become off-balance and slack.
5. What causes the mountain bike chain to jump?
If you notice your mountain bike chain jumps-off while you ride your mountain bike, the most common cause can be a loose cable.
Your mountain bike cables stretch with time and excessive use.
Most stretching will take place within the first few rides after you install a new cable, but older cables will stretch a lot.
This is when the trouble starts.
Without sufficient cable tension for properly regulating your derailleur, your MTB chain will begin to jump.
6. Why is my MTB chain loose when I stop pedaling?
Your MTB chain typically becomes loose when it wears off or when the link becomes stiff or bent.
If your chain is clogged up with dirt, it wouldn’t need another reason to hang loose.
The other possible reasons for your MTB chain being loose are the vent chain ring and chainring tooth.
7. What does a loose bike chain sound like?
If you consistently hear clunks and clatters from your MTB chain, you can suspect that your mountain bike chain is skipping under load.
8. Why does my mountain bike creak when I pedal?
Mountain bike typically creaks due to dirty or dry bearings.
Pro mountain bikers hear noises usually when they ride in dry or harsh conditions.
9. How do I know if my mountain bike bearings are bad?
Consider replacing your bike bearings when you hear loud noises or if there are gaps or bumps.
The thought of detecting the problem of your mountain bike chain skipping under load on your own and even fixing it will make your feel exhausted.
The main reason behind your new mountain bike chain skipping or shifting more than once is simple.
After you check each component, find out if it is properly aligned.
If there is any damage in your MTB, then you can figure out the main issue very fast.
Use the simple techniques and methods mentioned above, you will find it easy to fix.
Of course, it is best to adjust the tension in the derailleur and shifting cable before you replace any parts.
P.S.Hopefully you found the post resourceful, if so then consider checking out our detailed deep-dives on how to remove a worn MTB chain with tools and without tools
Team Biking KnowHow
Rohan runs Biking KnowHow along with his team. Rohan has been a mountain biker since 2005. His mission is to simplify mountain biking for everyone. All Biking KnowHow content piece is thoroughly fact-checked. Our content is backed up with leading research and inputs from expert cyclists.
Most of the time, a skipping chain is caused by cable stretch. In the first half dozen rides on a new bike, your shift cables stretch the most. They can also stretch over time as you ride. Hippley explains, “It takes cable tension to open a derailleur, which shifts your chain between gears.Why is my bike chain skipping under load? ›
Most of the time, a skipping chain is caused by cable stretch. In the first half dozen rides on a new bike, your shift cables stretch the most. They can also stretch over time as you ride. Hippley explains, “It takes cable tension to open a derailleur, which shifts your chain between gears.Why is my bike chain skipping when I pedal hard? ›
Gear indexing issues
One of the most common reasons for a skipping chain is simply a drivetrain that needs a simple indexing adjustment. This is so common that even many brand new bikes can exhibit these symptoms. The good news is that this is probably the simplest to diagnose and fix of all potential issues.
Check if the teeth are significantly worn (shark tooth shaped) and if the chain rides up the teeth under torque. If thats, the case, then your chainrings may need replacing. It would be very unusual for all three chainrings to be worn out. The skipping is basically cog/chain ring independent.Why does my bike chain slip under pressure? ›
Other problems associated with a worn drive train are bushings coming out of the chain, bent cog or chain ring teeth, and individual teeth breaking off of cogs or chain rings. All of these problems can cause a chain to skip while under pressure.Why is my chain skipping on the smallest cog? ›
Probably the chain it too long. Shift into your lowest gear and see if there is enough slack to take out a full link.How do I stop my chain from bouncing? ›
Try backing off your effort (but still pedalling) when shifting between chainrings. Another way to keep the chain from coming off the inside of the chainset is to use a chain catcher. A chain catcher is essentially an arm that acts as a barrier to the chain overshifting inwards.Why does my bike chain skip after new chain? ›
Most of the time, the slipping of a new bike chain is caused by loose cables. The new shifting cables stretch a lot during the first few rides. The cables stretch way too far with time, and that's when the problem arises, and your chain starts to slip between gears.Why is my chain skipping a gear? ›
Gear cables can stretch over time and derailleurs can be knocked out of alignment. If you find your chain is skipping a gear or that your shifting is getting stuck, then there's a good chance you need to adjust your gears. This is also known as indexing your gears.Why does a mountain bike chain slip? ›
Slipped bike chains may be caused by several different problems including poor shifting technique, the chain being too long, or a worn out chain or rear casters.
Hard Shifting With a Heavy Load
Shifting under a heavy load, such as when you are pumping hard on a climb, can cause extra stress on the chain and cause it to snap. Even ordinary pedaling while shifting can put stress on a chain. Shift before a climb and back off pedaling when you shift to avoid snapping your chain.
If your chain is getting slack on top when you stop pedalling or backpedal, then the problem is in your freehub (or freewheel, whichever you have), a dirty freehub will cause all the problems you've listed, even on a brand new bike.Should there be slack in a bike chain? ›
There should be approximately one half inch of movement in the chain up and down at a point half way between the front and rear sprockets. To change the tension loosen one of the axle-nuts and move the wheel forward or backward slightly and snug it up again.Will a new chain stop skipping? ›
When you replace the chain while leaving the old cassette the tooth profile is no longer correct and the new chain will skip off of the teeth, especially under load. Unfortunately it won't get better and the only recourse is to replace the cassette as well.Should the front derailleur touch the chain? ›
The front derailleur cage should be approximately parallel to the chain. If the derailleur cage is rotated too far from this position, it will shift poorly. If the derailleur mount is a clamp type, its rotation can be changed. Generally, the outer cage of the front derailleur should be aligned to the chain.How long does a bike chain last? ›
Most mechanics agree that you should replace your chain about every 2,000 to 3,000 miles, depending on your riding style. Many Tour De France riders wear out two or even three chains on their primary bike over the course of the three-week race.What happens if my bike chain is too long? ›
A chain that's too long (loose) may cause dropped chains and/or inconsistent shifting — front and back shifting. A chain that's too short (tight) can cause even bigger problems.What causes ghost shifting on a mountain bike? ›
A bike shifting gears on its own is referred to as ghost shifting. This occurs when the cables in your bike become loose over time. Additionally, there may be friction within the cables, the derailleur might be bent because of cable tension, limit screws may not be set properly, or the entire chain has broken.Can you use wd40 on bike chains? ›
In summary, WD-40 is great for cleaning and degreasing your chain, but doesn't work well as a lubricant. It will provide some small amount of lubrication, but nowhere near enough for your bike chain to run smoothly. It's best to use a high-quality, bike-specific lubricant instead.Why does a chain jump on a sprocket? ›
A common cause of chain climbing or even jumping its sprockets is excessively worn sprockets, or worn chain, or both. Worn sprockets will also cause chain to wear rapidly, so it's important to replace it and check the condition of the sprockets before fitting new chain.
The rule of the thumb says that the exact tightness of a chain will only let you move for about half an inch. Now, if the chain is too loose, then you need to tighten it. If you cannot even move the chain, then it is too tight, and it needs to be loosened.Why does my bike chain suddenly slack? ›
One of the most common reasons is a new chain on an old bike. Older bikes obviously have older and more worn-down components. Placing a new chain on these worn-down parts can cause the chain to jump and slip around as you ride. All of this motion will eventually cause the chain to loosen up.Are expensive MTB chains worth it? ›
The quality of the bike chain you use will affect chain weight, shifting performance, long-term durability, friction, and shifting noise. A higher-quality chain will be lighter and provide better performance overall.Why does my chain break so easy? ›
Chains break for a host of reasons, but most common is wear. For example, if a chain has been ridden for 2500 miles, it will actually stretch out. Correspondingly, a ridden chain will be longer from link to link than a new chain. Because the chain is stretched, the metal fatigues is more susceptible to failure.How common is broken bike chain? ›
A broken or bent chain on your bike is super common, so knowing how to remove sections of your chain and reinstall it is a necessary skill to have.How tight do chains need to be? ›
The chains should be tight on the tire. And, be sure to stop if you hear them making any contact with your vehicle. If your chains are still loose, unhook the bungee and adjust the red hook straight across from the chain guide. Unhook and reattach to the tightest position on one of the three gold chain links.How much should a chain stretch? ›
The number most commonly agreed on for a worn chain is one per cent elongation between links. In reality though, you should replace the chain before this point. So, therefore, anything past 12 1/16in (0.5 per cent) would be the time to replace a chain.Why does my chain click when I pedal? ›
A clicking noise often comes from your chain wanting to jump up or down a gear on the rear cassette. This can typically be fixed by adjusting the tension of the cable that runs from your shifter to your rear derailleur.How often should you leave your bike chain? ›
Optimal: Clean your chain after every ride, especially after riding in wet conditions. Recommended care intervals: Road bike: Ideally after every ride, at the latest after 250 km or at least once a month. MTB, cross and frequent riders in all weather conditions: After 100 km at the latest.How much slack should be in a chain? ›
For normal drives, adequate slack should be adjusted to 4% of the chain span. [Example, if the chain span is 46.5", slack should be 46.5" x 0.04 = 1.86"] (C).
A “slack” angle is anywhere from 63 to 66 degrees. This means the fork of the bike is going to stick out farther, creating a more stable ride at high speeds, but also be slower handling.What causes a chain to ride up on a sprocket? ›
Buildup can occur between the teeth – making it difficult for the chain to properly seat in the sprocket, causing the chain to ride higher on the tooth. In this case, cleaning the sprocket or utilizing a self-cleaning sprocket will resolve the issue.What are the reasons for skipping gears cranks on a bicycle? ›
- A Loose Chain.
- Gear Indexing Misalignment.
- A Worn Chain.
- Worn Chainring And Sprocket Teeth.
- Wrong Spare Replacements.
- A Dirty Drivetrain.
- Shifting System Error.
- Spoilt Freehub.
The cause is some friction or hangup of the chain in the RD as you backpedal. This unloads the chain and it will follow it's path of least resistance. A brand new chain is less laterally flexible and will highlight the problem of hangup at the RD.Why does my chain go slack when I stop pedaling? ›
If your chain is getting slack on top when you stop pedalling or backpedal, then the problem is in your freehub (or freewheel, whichever you have), a dirty freehub will cause all the problems you've listed, even on a brand new bike.What does ghost shift mean? ›
Ghost shifts are often run using marginal material intercepted on the way to the grinder that would normally be disposed of, but for the most part, the markings and characteristics of the material will often look absolutely authentic because the “ghost” material is indeed genuine, albeit without the brand's stamp of ...What causes bike chain to coming off front sprocket? ›
It might be that the chain is worn, has a stiff or bent link, or has become clogged up with dirt. A visual inspection while turning the cranks should reveal if there's a problem here. The chainring, or a chainring tooth, could be bent. Again, a visual check will tell you what you need to know.How do I know if my chain sprocket is bad? ›
Worn sprocket teeth are clingy. They hold on to the chain longer than needed. Sometimes the chain can even climb the teeth. This interaction will make a lot of noise.Why does my rear derailleur click when under load? ›
A clicking noise often comes from your chain wanting to jump up or down a gear on the rear cassette. This can typically be fixed by adjusting the tension of the cable that runs from your shifter to your rear derailleur.