Hi folks,
I’m having trouble after replacing the chain on my e-bike. Something is slipping under load in certain sprockets, and I can’t figure out what’s wrong.
Bike & Drivetrain:
- Bike: Birk E-SUV (Ebike)
- Cassette: Microshift CS-H103A, 10-speed, 11–42T
- It is a single chainring in the front
- Rear Derailleur: Microshift RDM62L, 10-speed
- Old Chain: KMC e10 Turbo with Quick-Link (almost 0.75% worn, replaced)
- New Chain: Shimano CN-E6090 E-Bike 10-speed
Symptoms:
After swapping the chain, I get intermittent slipping under power in specific gears (not all, just the 5 smallest sprockets are failing (except the very smallest to the far right, that one is OK)). It feels like the chain is skipping or not catching properly on the cassette. The derailleur indexing seems fine, and shifting is crisp. I measured the cassette with a Unior sprocket wear indicator, and the misbehaving sprockets show no excessive wear.
Here’s a video showing the problem: https://www.youtube.com/shorts/ZCc4slSd1kc (same as attached)
Any ideas on what’s going on? Could it still be wear-related even if the gauge doesn’t show it? Chain compatibility issue? Derailleur alignment? Freehub issue?
Thanks in advance!
New chain slipping on cassette on certain sprockets
byu/kapell inbikewrench
by kapell
18 Comments
Chains and cassettes often wear together, especially if they are run too long. Likely you need to replace the cassette as well.
This is consistent with cassette wear, especially if the affected sprocket is one that you’ve used a lot in the past.
If that’s the case you’d need to replace the cassette as well.
“After swapping the chain…”
There you go, that’s why, new cassette time!
As stated, as a chain wears, it tends to wear the cassette to match. That usually happens on the most used sprockets which is why your chain works ok on some gears.
Replace the cassette asap (or it will in turn wear your new chain to match!).
You should have changed the chain way earlier, now you need to change the cassette as well. The most common replacement rate is 2 chains x 1 cassette, so you should buy a chain wear indicator and inspect your chain once a month to replace promptly thus avoiding excessive wear on a cassette.
Replace the cassette and it should be fine. Ideally you would replace the chain ring as well.
If you take care of your drivetrain and replace your chain when it hits its minimum wear your cassette should last a while. If your cassette has visible wear or in this case slipping I would replace it. Don’t buy into the addage that you need a new cassette any time you get a new chain. I’m not replacing a $300 cassette any time I have slight wear in my chain.
Setting aside the question, huge kudos to OP for including a video which is actually helpful and focussed clearly in the problem area for more than a quarter of a second.
The chain is catching at a tooth in the adjacent (larger) cog as it’s coming off the upper pulley. I’ve seen this happen with new chain + new cassette + new RD, and I’ve also never had this happen with a used chain + used cassette + used RD (all parts sourced independently and with unknown history) that’s dialed in, so I’m leaning towards this being an adjustment issue and not a wear issue.
You might be able to get rid of this issue via a combination of adjusting cable tension (making sure the top pulley is aligned with the cog using the barrel adjuster) and increasing or decreasing the derailleur pulley-cog clearance (B screw).
Did you install the master link on the new chain upside down?
How did you make this video?!
It’s hard to see in the video, but confirm that quick connect link is fully engaged. I’ve seen this issue many times in the subs.
Wrong? You replaced just the chain and not the cassette
It might be time for a new cassette, if you leave the chain on for so long chances are the casssette will be affected, and will cost more money on the long run.
that video perspective was awesome haha
Probably need a new cassette too.
Your jockey wheel pivots just before it slips. May have a tight link or two. But chain/cassette wear is likely as others have pointed out.
Before trying on a new cassette, try[ this method](https://www.youtube.com/watch?v=UkZxPIZ1ngY&t=21s) to make sure that the rear derailleur is set perfectly. If that doesn’t work, it’s probably a problem with the cassette. Cassette wear is very hard to detect visually, it’s much easier to see wear on the chainring. There shouldn’t be that much wear after just one chain swap, I know my cassettes last much more than that, but maybe microshift sold you a bad one? The only way to know is to get a new cassette and try it out.