I removed my cassette, cleaned it and put a new chain on my mountain bike. All seemed to go well and went back together nicely. However when I took it out for a ride the free hub seems to be slipping with a sort of judder. It's like it engages, but then slips almost like the chain is slipping.

I'm fairly confident it's not the chain slipping though as it's doing it an every gear (more so in lower gears where there is more tension) and the derailleur doesn't seem to bounce/move at all when it slips.

I pulled the cassette back off to check it all looked like it's assembled correctly, but I see nothing wrong.


Update 1 I've inspected the cassette fairly thoroughly and am fairly convinced it's not warn. There is no angling on the teeth and no visible sign of the chain not sitting properly. Watching it carefully and it looks like the cassette is spinning with it when it slips, not the chain slipping over it.

The old chain wasn't massively overused, it'd been on the bike maybe 8 months and done maybe 1000km. It was replaced due to a link failing, not because it'd warn out.

It's slipping a lot almost to the point it's completely unrideable. I'll stick the old chain on later and see if it stops, but I can't see such a massive difference being likely?

Update2 Thanks for all the answers trying to help. I've added some photos of the cassette. https://i.stack.imgur.com/zwqiT.jpg

Cassette - pic 1

Cassette - pic 2

  • 2
    My question relates to the freehub slipping, not the chain. This is not a duplicate?
    – Graeme
    May 4, 2016 at 13:43
  • either the cassette does not pull the freehub, or the freehub itself is not holding. could be simply some piece you put backward? how does it go in reverse? is is still free-wheeling?
    – njzk2
    May 4, 2016 at 14:25
  • @njzk2 Yes, it freewheels fine in reverse. There is no sign of damage to the outer of the freehub, so I doubt it's the cassette not binding to that.
    – Graeme
    May 4, 2016 at 14:52
  • 1
    can you add a closeup photo of the cassette, to convince people that it is not over-worn?
    – njzk2
    May 4, 2016 at 14:56
  • 1
    Also it could be worth giving the cassette a quick wipe before taking a photo as some may interpret the oil/grease for wear without looking at all the teeth.
    – Rider_X
    May 4, 2016 at 21:28

2 Answers 2


It is likely that your cassette is worn.

A new chain on a worn cassette will skip, because of the mismatch of the shape of the teeth on the cassette with the chain's spacing (which is shorter than what the cassette expects due to wear).

You can visually inspect your cassette for wear by either looking for gaps in how the chain meshes with the cassette, or looking at the teeth to see that they aren't well shaped.


Your cassette is worn and needs replacing too. I bet the old chain was well past replacement time, and it wore into the cassette. Now you've changed the chain, it no-longer makes good contact with all the teeth at once.

Stop riding immediately - fit a replacement cassette ASAP else you'll be up for another new chain.

Do use the search functions of this site. Your question is a duplicate of New Chain causing skipping on cassette - will this work itself out or is it unsafe?

Also do read the Tour under the Help menu to learn how the site works.

  • 1
    I suggest looking at the photo the OP attached, the cassette doesn't look particularly worn.
    – Rider_X
    May 4, 2016 at 21:29
  • 1
    @rider_x yeah that looks worn to me. A photo of the new chain wrapped around it will show light between them, before and after the one tooth/roller that is actually making contact and carrying the load.
    – Criggie
    May 4, 2016 at 23:21

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