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Does your chain start slipping when trying to speed up your bike? It usually happens when you try and pedal hard and it’s definitely a mood killer when it happens!
Cycling at high speeds can result in your bike chain skipping or slipping. If continued for an extended period, the process can lead to damaged components like the cassette.
In this post, I’ll look at the 11 most common reasons why a new bike chain might slip when pedaling hard. I’ll also look at the fix to each of these situations.
In most situations, it’s reasonably easy to diagnose the problem and fix it (trust me!). If you’re OK at taking bits of your bike off and then putting them back on, then it’s all very doable without a mechanic (and I’ll give full details on how to do this).
1. New Chain Slipping Because Of Loose Cables
This is the numero uno of reasons why this happens!
The most common problem of new chains slipping when pedaling hard is stretched cables that become loose.
This is a frequent problem with new bikes.
Cables become stretched over time and they start to lose their positioning along the gears.
How To Fix
This is simple to fix as it requires an adjustment of the chain tension. You can do this in a few easy steps that can be done without requiring you to completely stop your biking session.
- Park your bicycle
- Set the bike chain on the smallest cog of the rear cassette. This is done by pedaling manually
- Press the shifter to double-check. If the chain doesn’t move up a gear, you need to add tension
- Twist the barrel adjuster on the right side to turn it away from you. The Barrel adjuster is a small part located at the back of the derailleur
- After this, press the shifter again to check if the chain moves up from the smallest cog again. Repeat the entire process if the chain does not move up to the proper adjusting position. Keep turning the adjuster until you find the appropriate spot and movement. You can get confirmation of this when the bike chain shifts normally.
- For the front derailleur, you can do the same process. But you will have to turn the barrel adjuster in the opposite direction (turn it towards yourself).
2. Tight Cables
This is similar to the first issue but in the opposite way (as you can probably guess!).
Your cables end up improperly adjusted to your bike’s drivetrains and that causes issues when pedaling or shifting gears. This is a problem that can happen to any brand of bike.
How To Fix
Follow the steps I mentioned above for loose cables but adjust the barrels in the other direction to loosen the tension on the cable.
3. Misaligned Rear Derailleur
Peddling hard can cause you to experience problems when encountering big bumps. This can cause the derailleur to become misaligned or bent.
This is a frequent problem because derailleurs are made up of fragile materials that can be easily damaged due to mechanical pressure.
The result is disturbed cable tension which leads to chain slipping.
How to Fix
- Check the structure of the rear derailleur hanger. If it is bent, you can adjust its shape by straightening it
- There are specific tools available for derailleur adjustments like wrench sets and special screwdrivers. It’s a good idea to get these tools. However, if you do not have professional-grade tools, you can use a large adjustable spanner. (Source)
- Check the rear wheel and the derailleur setting again to see if it is aligned
- You can also align the derailleur but adjusting the nut that connects the shifter cable to it
You can learn more about rear derailleur adjustment in this video:
4. Poorly Positioned Front Derailleurs
Sometimes the front derailleur can be badly positioned. This can harm chain movement, which can slip along the gears.
You will have to check its positioning. I’ll be honest – fixing this is better done with professional help.
However, there are some steps you can take to fix the issue if you are pretty savvy and confident to have a go:
How To Fix
- Check the fort derailleur positioning, height, and screw setting
- Move the derailleur arm over the outermost ring. The distance between the outer cage of the derailleur and the chain should be as small as possible, without making contact (this should approximately be 2 mm). You can use a thin coin to gauge this distance
- Loosen the mounting bolt to reposition the derailleur. You can find this on the opposite side of the seat tube
- Consider loosening the derailleur cable to adjust it easily over the outermost ring
- Be sure to tighten all the screws again.
5. Won-Out Or Damaged Cogs
Wear and tear is a routine part of biking. Peddling hard can exacerbate the problem.
As your bike grows older, your chainring and cassette will eventually be damaged due to friction. The teeth of the cogs get damaged and are unable to hold the chain in place.
This is something that the experts at SRAM also acknowledge. (Source) It is not unusual to detect broken cogs until very late in their life cycle (no pun intended!)
How To Fix
You need to replace the damaged sprockets and cassettes immediately.
You can do this yourself, or get help from a professional. This is advisable if you have a new chain, as it can get deformed quickly.
Alternatively, you can replace the entire chainring. Fixing this problem is straightforward, but you need to know the correct tools and standards for your bike.
In other words, refer to your bike manufacturer’s instruction manual.
6. Dirty or Greasy Sprockets
This is one of the easier issues to diagnose.
Constantly riding your bike outdoors can lead to a buildup of dirt on the cassette, causing the cog teeth to become obstructed.
Grime can also build up due to excessive use of grease. The result is sluggish chain movement and gear shifting.
This is why you should regularly clean your sprockets and cassette. Failing to do so can also lead to premature damage to the chainring.
How To Fix
- Remove the cassette from the wheels by unscrewing it from either side. Place the cassette in a bowl filled with degreaser. The cassette should be completely submerged in the liquid. Let it stay for several minutes
- Remove the cassette from the bowl and scrub off all the dirt from the sprockets using a toothbrush
- Re-oil it and place it back. Be careful about wheel alignments when reapplying the screws
- This process can be inconvenient, especially if you’re worried about alignments. You can use a pipe cleaner or small rug to clean the cassette routinely to minimize the need to remove it frequently.
You can learn about cleaning your bike chain in this video:
7. Old Shifting Cables
If your bike’s shifting cables are old, there’s a good chance they may be rusty or bent. Such problems with shifting cables will result in improper gear shifts and chain slipping.
This can also cause a sudden breakage, and you could even risk an accident.
The only solution to this is to swap out the old shifting cables for new ones. If the damage is significant, we also recommend changing the housing around the cable.
How To Fix
- Shift your bike into the smallest gear setting
- Turn the adjuster all the way inside
- Loosen your derailleur clamp and pull out the cable from its position
- Check the length of the cables you need to install. Your old cables are a good reference point for the required length. If you are still unsure about the length, leave a couple of extra inches to give yourself some room for making adjustments.
- Insert the cable into the shifter and close it
- Adjust the cable into the derailleur as required
- Pull the cable in, tighten it, and then fasten the derailleur to its correct position.
- If you have extra cable left over, cut it down to the correct size
- Check the position of the derailleur. (See the information in sections 3 and 4 above)
8. Old or Damaged Shifters
Shifters help keep shifting cables in position by providing the right amount of tension.
If the shifter is damaged due to wear and tear, it will cause the shifting cable to lose tension, and your chains will miss gears.
Sometimes shifters are also made of poor-quality materials, and the same thing will happen.
How To Fix
- Remove the grips from the handlebar side by periodically twisting them. You can use a butter knife and some water to help you with the process.
- Shift the chain into the smallest gear setting.
- Unbolt the cable from the front or rear derailleur
- Remove the cable from the body of the shifter
- Remove the shifter assembly. This can vary depending on the type of shifter in your bike. Sometimes shifters can only be removed after removing housing screws. Other shifters have levers to keep them in place.
- Install the new shifter by sliding it onto the correct handlebars
- Thread your shifting cable back into the new shifter, and route it through the derailleur
- Add lubricant to the shifting cable and tighten the screws of the new shifter back again.
- You should test the shifter to see if your bike shifts all the gears correctly. If it does not, adjust the cable again and recheck the shifting.
9. Incompatible Chains
Your bike might require a specific chain using a different chain can cause it to be misaligned and slip across gears.
How To Fix
Check your bike manual for the chain specifications. You can buy the appropriate chain from your local bike shop (hopefully).
Top Tip – If you are buying a new bike, always check the compatibility and availability of chains. This will save you future headaches.
10. Wrong Chain Length
Chain length is an important performance factor for your gear shifting.
A short chain can exert stress on the drivetrain, and damage it. A long chain will slip too much, making gear-changing a nightmare.
Many commercial bike chains come with 116 links. This is typically more than the requirement for most bikes. So you might need to adjust the chain length by removing some links.
How To Fix
When buying a new bike chain, hold it against the old chain to count the required links.
However, older chains change lengths, so you need to check if the links are the right length.
You can also use the ‘big-big’ method to measure the required chain length. Put the chain around the largest chainring in the front and the largest sprocket in the rear. Do not slide it through the rear derailleur.
You should leave one inch or one link for the derailleur, and ensure the chain has the correct tension. This will tell you the exact chain length you need.
11. Excessive Lube
An excessive amount of lubricant on the chain will cause your sprockets to lose contact with it.
Your chain and sprockets will literally be slippery. Too much lube will also cause more dust particles to accumulate, leading to more damage over time.
How To Fix
You need to clean your chain using a cloth after any excessive greasing and use a small amount of lubricant when re-greasing your bike
As you can see, there are many reasons why your chain can slip.
At first, it may seem overwhelming to think about detecting the cause of the slipping.
But often, the reason behind poor bike performance is very simple. I hope this guide equips you with the know-how you need to solve any issues with your bike chain.