Chain skips under heavy load when pedalling

[Zviedrs]

Hey. My 1x mountain bike has been very reliable for over 2+ years, with no problems whatsoever. But recently I have been annoyed by chain skipping when under heavier load. Honestly, I have not changed the chain, nor chainrings. I have some experience with 2x and 3x front chainring drivetrain systems but 1x is still new to me. What would be your first move? I don't think that the cassette is worn out.

• inspect the chain and chain wear?
• adjust the rear derailleur?
  

[FabioMaria]

(10-13-2021, 04:59 PM)Zviedrs Wrote:  Hey. My 1x mountain bike has been very reliable for over 2+ years, with no problems whatsoever. But recently I have been annoyed by chain skipping when under heavier load. Honestly, I have not changed the chain, nor chainrings. I have some experience with 2x and 3x front chainring drivetrain systems but 1x is still new to me. What would be your first move? I don't think that the cassette is worn out.

• inspect the chain and chain wear?
• adjust the rear derailleur?
  

how much the chain in worn out?
do you have a caliper? it would be more accurate: check if the caliper set up at 133mm can be inserted or worse if it can move freely

[JoJoJo]

for those who stumble upon this thread and are wondering how to check for chain wear: https://www.bikeride.com/chain-wear/

[ReapThaWhirlwind]

Also consider your chain is too long and needs to be cut shorter.

This always happens to me on my single speed with a bolt-on chain tensioner when I add a new chain and don't cut it tight enough.

Reason for this being, I previously bent the rear axle on this bike from running it without a tensioner with the chain way tight. Trying to prevent this from happening again as I'm a Clydesdale and tend to get up on it HeYAW!

[Jesper]

(10-13-2021, 04:59 PM)Zviedrs Wrote:  Hey. My 1x mountain bike has been very reliable for over 2+ years, with no problems whatsoever. But recently I have been annoyed by chain skipping when under heavier load. Honestly, I have not changed the chain, nor chainrings. I have some experience with 2x and 3x front chainring drivetrain systems but 1x is still new to me. What would be your first move? I don't think that the cassette is worn out.

• inspect the chain and chain wear?
• adjust the rear derailleur?
  

Did you get this sorted out? I am curious to know what the problem was.
With proper chain/drivetrain maintenance you should not need to be replacing any components (chain, chainring(s), cassette cogs) if the bike (or components) was new when you obtained it unless you have put 1000s of Kms on it since. I would certainly have had the chain checked for wear and done a visual inspection of the cogs. You shouldn't have needed to "trim" the chain length if it workedd adequately for 2 years without any issues. In cases like this where I wasn't able to check my chain wear (I still do not have a gauge; I should!), I would remove it and compare it to a new chain (which I always have), swap out with the new chain, or swap out with a good used chain and see if the problem persists. If you had made no alterations before this problem and the bike has remained set-up the same than the chain would be the prime suspect. I tend to get 5000 + Kms on a chain that started new and was maintained properly; reduce that by half or more if just doing basic on the bike chain cleaning; especially on any bike used off-road.

Please provide your update so we can all learn from your experience regarding this problem.

[Zviedrs]

(03-28-2022, 03:02 PM)Jesper Wrote:  

(10-13-2021, 04:59 PM)Zviedrs Wrote:  Hey. My 1x mountain bike has been very reliable for over 2+ years, with no problems whatsoever. But recently I have been annoyed by chain skipping when under heavier load. Honestly, I have not changed the chain, nor chainrings. I have some experience with 2x and 3x front chainring drivetrain systems but 1x is still new to me. What would be your first move? I don't think that the cassette is worn out.

• inspect the chain and chain wear?
• adjust the rear derailleur?
  

Did you get this sorted out? I am curious to know what the problem was.
With proper chain/drivetrain maintenance you should not need to be replacing any components (chain, chainring(s), cassette cogs) if the bike (or components) was new when you obtained it unless you have put 1000s of Kms on it since. I would certainly have had the chain checked for wear and done a visual inspection of the cogs. You shouldn't have needed to "trim" the chain length if it workedd adequately for 2 years without any issues. In cases like this where I wasn't able to check my chain wear (I still do not have a gauge; I should!), I would remove it and compare it to a new chain (which I always have), swap out with the new chain, or swap out with a good used chain and see if the problem persists. If you had made no alterations before this problem and the bike has remained set-up the same than the chain would be the prime suspect. I tend to get 5000 + Kms on a chain that started new and was maintained properly; reduce that by half or more if just doing basic on the bike chain cleaning; especially on any bike used off-road.

Please provide your update so we can all learn from your experince regarding this problem.

Hey Jesper. How are you doing? I will give an update at some point - it's not sorted completely
I biked through the winter and will perform proper maintenance in 2-3 weeks or so. I haven't done serious training rides with a heavy load, mostly commutes (bad winter weather, rain, etc.) and pleasure rides without much stress on the chain. Gave my Merida a spray wash recently and pedaling got better. I sense that this is mostly about the chain - it obtains lots of dust and sticky, sticky dirt. As a result, pulley wheels are also clenched with this dust. Also, I will have to adjust FD.

[Jesper]

(04-24-2022, 02:53 PM)Zviedrs Wrote:  [
Hey Jesper. How are you doing? I will give an update at some point - it's not sorted completely
I biked through the winter and will perform proper maintenance in 2-3 weeks or so. I haven't done serious training rides with a heavy load, mostly commutes (bad winter weather, rain, etc.) and pleasure rides without much stress on the chain. Gave my Merida a spray wash recently and pedaling got better. I sense that this is mostly about the chain - it obtains lots of dust and sticky, sticky dirt. As a result, pulley wheels are also clenched with this dust. Also, I will have to adjust FD.

The "sticky" chain could certainly be all or part of the cause.
I have been using my own chain lube mix developed by accident. I tested some wax suspended in a solution lube I bought, but I did not like it due to the chain noise (creaky and squeaky) and it got stored away. Months (or years?) later I went to use it on something else, but the solvent liquid had evaporated and there only congealed wax at the bottom.
A short time later I wanted to test synthetic motor oil as a medium viscosity chain lube, and I poured some oil into the "empty" (I forgot about the wax) liquid wax bottle for ease of applying the oil. I could not understand why the oil had gotten milky, and then I realized that the oil had broken done the wax and it was now a solid lubricant suspended in a liquid lubricant. How could I go wrong, but be so right. That stuff runs very quiet, even on my older equipment; not sticky, less grit adhering. I might need to patent the mix (notice that I provided no brand names!). I have only used it on drivetrains externally; cogs and chain.

[Lss555]

I would check to see if you can take a chain piece off your chain so it’s tight and make sure you have oil on your chain. I use to have the same problem and those two things fixed it

[SPINMAN]

(10-13-2021, 04:59 PM)Zviedrs Wrote:  Hey. My 1x mountain bike has been very reliable for over 2+ years, with no problems whatsoever. But recently I have been annoyed by chain skipping when under heavier load. Honestly, I have not changed the chain, nor chainrings. I have some experience with 2x and 3x front chainring drivetrain systems but 1x is still new to me. What would be your first move? I don't think that the cassette is worn out.

• inspect the chain and chain wear?
• adjust the rear derailleur?
  

Two years is a long time on a mountain bike, where shifting is often done under pressure. For sure, the chain has "stretched." The easiest and cheapest solution would be removing a link or at least changing the chain. If the cassette is worn, which is likely, you will know when it keeps skipping with the new chain.

[Sybian]

(01-15-2023, 10:23 AM)SPINMAN Wrote:  

(10-13-2021, 04:59 PM)Zviedrs Wrote:  Hey. My 1x mountain bike has been very reliable for over 2+ years, with no problems whatsoever. But recently I have been annoyed by chain skipping when under heavier load. Honestly, I have not changed the chain, nor chainrings. I have some experience with 2x and 3x front chainring drivetrain systems but 1x is still new to me. What would be your first move? I don't think that the cassette is worn out.

• inspect the chain and chain wear?
• adjust the rear derailleur?
  

Two years is a long time on a mountain bike, where shifting is often done under pressure. For sure, the chain has "stretched." The easiest and cheapest solution would be removing a link or at least changing the chain. If the cassette is worn, which is likely, you will know when it keeps skipping with the new chain.

I am not a bike mechanic, but I know mechanical devices on a professional level. They all act the same regarding worn parts, troubleshooting, and servicing. I deal with chains and power transmission on a much higher scale than that used on a bike.
Get your chain measured! If worn replace it; if not worn then check all associated parts for wear and proper set up. Removing a link is not the answer, and it is not an acceptable means of troubleshooting since you are probably using a bad part as an indicator to try to determine if you have other bad parts.
My experience would dictate that if a chain is indeed worn you need to replace it, and not remove a link unless it is just to get you by in an emergency situation until you can have it measured or replace it with a new chain. If a chain is worn so much that it affects the drivetrain (assuming the cogs are not worn, and set up is correct) it indicates that its geometry is longer any good, and using it will only cause residual damage to the cogs, especially the alloy gears. This apllies to all mechanics (industrial, automotive, sports, etc.) since when utilizing a worn part, any other parts in contact or integrated to its operation will still be affected and will in the end become worn/damaged quicker than they would if replacing the "bad" part with an adequate replacement. I have worked on high volume computer controlled electro-mechanical processing equipment where it is more readily obvious when a small difference in performance makes a very big difference in the results and saves you (or your company) a lot of money and time since you avoid performance/output loss from downtime and replacing other parts that would never have needed replacement if you simply did not take a shortcut by using a worn part when a new part was readily available and easily replaced at low cost and with very little time expenditure.
In short: if the chain measues wear that is out of spec. just replace it.
Bikes are cheap compared to autos and industrial equipment, but service and preventative maintenamce should be carried out in the same manner; immediately if possible using the correct parts. Pull out a link for tomorrow's ride and all you do is cost yourself more time and money in the long run.