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A mountain bike chain skipping under load is 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.