Cassette rattle

aidsowmb

I've a set of DT Swiss M1700 wheels that came on my Canyon and there's a big rattle from the cassette area.
It's an 11 speed and i've noticed the 3 biggest cogs move ever-so-slightly from the remaining 8 cogs. I replaced the cassette and it looks to be the same issue. The lock-nut is defo tight.
The thing is, they don't always move (ffS). When the chain is around one of these cogs I thought it was holding them tight and therefore only rattled when in the middle of the block.
But if I drop the chain away then the cassette feels tight with no movement in the cassette.
Any ideas why they rattle and then don't? I haven't noticed any "smoothness" in the outer free hub that would be causing the cassette to slip but will look again.

rip_van

Is it 1x? Is it xd?

aidsowmb

It's a 2x11. I've taken a video of it. This is a new cassette after 2 rides still in thinking it's something else

https://youtube.com/shorts/icyPLTxOe7o

nibnob21

Worn splines on the freehub? This would be unusual for the granny gears as they're normally fixed together so the load is distributed across the splines over a greater area. Normally it's the single cogs that can chew the freehub.

steve_sordy

Have you got a cassette spacer missing? If the cassette nut is tight, then the individual parts of the cassette should not rattle. The whole cassette may move back and forth very slightly , but the individual gears should be locked together. If they move independently there is a problem.

aidsowmb

I took the whole thing off again last night and there were no splits or cracks on the freehub. I've tightened it up with more effort again and will keep an eye on it over the weekend.

aidsowmb

The saga continues...had a good session yesterday but after an hour the cassette has managed to come loose again. I'd it tightened up pretty tight by hand but the vibrations are undoing that. I don't have this issue on any other bike

Allan154

is there not a washer thin large job that goes on to take up that slack ?. I remember my road bike having a Mavic hub 10spd and you needed a Mavic washer similar to this;-

https://www.lordgunbicycles.co.uk/mavic-m10-original-spacer-175-mm-for-shimano-sporcket?option=3766&destination=GBR&currency=GBP&gclid=Cj0KCQjw38-DBhDpARIsADJ3kjmrwdnJJ8YbVOVw86GHX7nFslSSOx17uDHZm4owF0jtbYwGrssD2yAaAiRoEALw_wcB

It's what you need when using shimano cassettes on a Mavic hub

just a guess

aidsowmb

I didn't need a spacer last month, wondering why I need one now ? It's almost like it needs a bit of loctite, but I'm sure that's not a thing for this component

steve_sordy

Cassettes come in a mixture of single rings and clusters of rings. I once had one of the clusters (a set of four I think) where the rivets had broken and the rings were loose. It was an undisputed warranty claim.

The fact that it wasn't rattling before and is rattling now could be explained by a gear cluster that has recently broken.

N0bodyOfTheGoat

Does the hub have screw on end caps to switch between QR and bolt thru, which have loosened, allowing the freehub/cassette to move side to side?