Stumped! Chain skipping

[broncobilly99]

Hey Folks, any suggestions?!

I have a mid range mountain bike that I perform maintenance and repairs on myself and am sbookered on how to fix a skipping chain.

Background.

I essentially just wanted to do some regular maintenance and decided on a new KMC chain. Same type/length as the previous one. Now it just skips under load in the higher gears, no hint of this on the old chain.

Removing the tension alltogether on the rear mech cable allows it to be stable in one gear.

What I've tried.

Two new chains.
Indexing multiple times.
Hangar straightening.
New shift cable.
H/l/B adjustment

Inspected cassette, seems reasonable and was skipping before.

Any pointers would be grand.

Cheers...

 

[raleighnut]

The gear teeth are worn, either replace the cassette/freewheel or put the old chain back on and run that into the ground.

 

[Paulus]

Worn cassette is most probably the cause.
Often with a new chain on an old cassette the new chain will skip.plus you state that it was skipping before the new chain.
Can you post some close up pics of the teeth on the cassette.

 

[Ian H]

Inspected cassette, seems reasonable and was skipping before.

I assume this is a typo.
New chain - old cassette.

 

[Ming the Merciless]

New chain , old cassette, or you’ve haven’t fitted a quick link properly and that is causing the skipping.

 

[Big John]

The gear teeth are worn, either replace the cassette/freewheel or put the old chain back on and run that into the ground.

A man after my own heart! 👍👍👍

 

[Ajax Bay]

Inspected cassette, seems reasonable and wasn't skipping before.

FTFY (and Ian)
One can't tell by eye whether a cassette has been worn beyond the state that it'll take a new chain (one reason why never to buy a 'not used much' cassette). As @raleighnut says: fit old chain back on or replace the cassette (to run with the new chain).
Edit after the image of that cassette!! Can see by eye that is worn way beyond . . . . Frankly I'm surprised the old chain wasn't slipping on some of those sprockets (2345).

 

[broncobilly99]

The gear teeth are worn, either replace the cassette/freewheel or put the old chain back on and run that into the ground.

Hi,

Thanks for the input. When I put the old chain back on it started skipping again.

I'll probably get a new cassette anyway tbf. I just don't get why it happened suddenly after swapping a chain out.

Cheers

 

[notmyrealnamebutclose]

Bit of a long shot as you've already tried 2 new chains but check for frozen link(s). My new but likely counterfeit shimano chain had
this problem with the chain jumping, especially around the jokey wheels. Still plays up when it's proper cold out.

 

[broncobilly99]

I meant to say the chain wasn't skipping before I replaced the old one, yes typo!

I fitted the chain powelink correctly.

Thnks guys. I'm going to order a new cassette I think.

 

[broncobilly99]

 

[ColinJ]

I'll probably get a new cassette anyway tbf. I just don't get why it happened suddenly after swapping a chain out.

A new chain fits a new cassette well.

Your old worn chain fits your old worn cassette well.

Your new chain does NOT fit your old worn cassette well!

I had exactly the same problem after fitting a new chain the evening before a local audax event. I lived less than 1 km from the start but didn't even get that far before the chain started slipping. I had to dash home and swap to another bike.

PS That cassette is EXTREMELY worn!

 

[Fastpedaller]

Those sprockets look too worn to me

 

[broncobilly99]

A new chain fits a new cassette well.

Your old worn chain fits your old worn cassette well.

Your new chain does NOT fit your old worn cassette well!

I had exactly the same problem after fitting a new chain the evening before a local audax event. I lived less than 1 km from the start but didn't even get that far before the chain started slipping. I had to dash home and swap to another bike.

PS That cassette is EXTREMELY worn!

Thanks buddy for the input and anecdote 😆 New one ordered👍

 

[broncobilly99]

Those sprockets look too worn to me

🫡🫣