Here's a random question for the hive mind...
Just been out for a short, evening ride around Houndkirk / Blacka Moor with my son. He's been mentioning a bit of a 'rattle' from somewhere around the back of the bike when riding fast over lumpy ground. I could clearly hear this rattle as I rode behind him. Assumed it was likely to be suspension pivot points. Checked all pivots for tightness when we got home - all seems fine. Checked every other bolt that I could - nothing amiss.
Finally gave the cassette a wobble and found that each individual cog can move on the freehub by around 5-10 degrees. Largest 4(?) cogs are a single assembly, so they wobble as a block of 4.
Used my chain whip to remove the cassette and it seems that the metal teeth which interlock onto the freehub are a bit worn and misshapen - giving rise to the wobbling.
I've never seen this kind of wear / play before - I'm presuming a new cassette is in order. Is this a 'thing' with 12s drivetrains? The bike's 3 years old and hasn't been ridden excessively (no hint of wear on the teeth / chain interface).
Any thoughts? Cheers!
Post edited at 22:56