Chain slipping

[RichKris]

Hi guys. I'm new to the forum so hello from Devon.
I have a 2021 Cube Reaction with a Bosch CX engine and a Haibike Hardnine 6 with a Yamaha engine.
On my Cube I recently noticed that while in gears 10 and 12 the chain started jumping/slipping. I did all the usual stuff like setting the gears up again which made no difference so took the wheel off after noticing slight play in the rear cassette. It has a Sram NX Eagle PG1230 cassette system and the first 4 cogs are fixed while the others go on individually. I took the cassette off and took it apart to give it a good clean. I then put it back on and tightened it up properly eliminating the play. On the stand the bike goes through all the gears smoothly and sounds good but when I take it out on the road, it's fine for the first 8 gears but now 9-12 are jumping/slipping. I scrutinized all the cogs of the cassette while it was off and they all seem good. I even took the bike to Halfords for their free health check and they also reckoned the cassette looks fine and the chain is also good. I'm now scratching my head trying to work out what's going on as I've done all the usual things. Does anyone more techy clued up then me have any ideas? Thanks in advance.

 

[HumanPerson]

Welcome to the forums mate

 

[RichKris]

Welcome to the forums mate

Thanks bud

 

[Titus]

Hi. I have just joined the forum today so I'm a bit late with a reply. I have a Cube Attention that I converted and have the chain slip issue you describe. mine happened at very hi torque situations and usually in the lower gears (but not always). My cassette looked good and the chainring is brand new, I also fitted a quality chain as well. I looked at the chain tension and decided I could afford to shorten the chain a couple of links which I did. This, touch wood, appears to have worked so far although I have not extensively tested so it's fingers crossed. From my investigations chain slip is a very common thing but chain length and worn chain rings and cassettes are prime suspects.

 

[RichKris]

Hi, thanks for your input. My slipping only happens in gears 9-12. I noticed my mech hanger was ever so slightly bent so
straightened it but but made no difference. Like yours mine happens under heavy torque so I'm convinced it's the cassette. What I'm not really sure of, is whether I need to stick with a Sram NX Eagle cassette or is there a suitable compatible one? There's plenty of swanky looking coloured ones on the net but are they any good?

 

[James340]

It can also be a adjustment issue.The barrel adjuster on the derailer might be to tight or loose.Does it shift precise and quick? Slow up shifting is loose and slow down shifting is to tight.

 

[RichKris]

Hi James. Yes I've had it up on the tune up stand many times and played with the barrel adjuster, limit screws and even the B- screw to make sure it changes gear seamlessly. Under torque it doesn't try to skip gears, it just misses on the 4 smallest cogs which would suggest they are probably worn.