Wobbly cassette - why?

[Mazz]

I eventually succumbed to the temptation to work on the bike at 10pm as guests had left...
I took off the cassette. As I expected, there was the usual plastic spacers between the gears. There was no spacer between lowest gear and wheel. There was a wafer-thin, buckled washer on the lock ring (is it meant to be that thin?).
Freehub seemed fine, no wobbling or excessive play.
Reassembled it and, for some reason, the cassette wobbliness has gone! I can't work it out. Maybe one of the gear spacers was misaligned? Really don't know. Anyway seems okay now.
Will see how it rides tomorrow.

 

[Slick]

I eventually succumbed to the temptation to work on the bike at 10pm as guests had left...
I took off the cassette. As I expected, there was the usual plastic spacers between the gears. There was no spacer between lowest gear and wheel. There was a wafer-thin, buckled washer on the lock ring (is it meant to be that thin?).
Freehub seemed fine, no wobbling or excessive play.
Reassembled it and, for some reason, the cassette wobbliness has gone! I can't work it out. Maybe one of the gear spacers was misaligned? Really don't know. Anyway seems okay now.
Will see how it rides tomorrow.

I still think that was threaded, but happy days the wobble has gone.

 

[Mazz]

I still think that was threaded, but happy days the wobble has gone.

What was threaded? Don't understand this.

 

[Slick]

What was threaded? Don't understand this.

The wafer thin washer on the lock ring was buckled.

Why was it buckled, was the lock ring threaded and tight on one half and loose on the other causing it to wobble?

Another possibility is that wasn't a washer, it could have been the remains of the damaged threads. Probably not, but it is possible.

 

[richardfm]

What was threaded? Don't understand this.

He means cross threaded.
"Cross threading occurs when a threaded connection engages at an angle rather than straight on. Cross-threading can damage the threading permanently."

 

[Ajax Bay]

This is a 10sp cassette on a 8-9-10sp freehub. You must have a 1mm spacer between the hub flange and the large sprocket. Without this the lockring bottoms out and even when it seems/is tight it's not applying required force on the cassette (hence wobble). (This maybe why a previous owner has randomly inserted this "wafer-thin, buckled washer on the lock ring".)
Shouldn't be there. The lockring interfaces directly with the smallest sprocket's (serrated) outer face. This results in the 'clicking' (x6) as you tighten the lockring to 40Nm.

 

[Mazz]

This is a 10sp cassette on a 8-9-10sp freehub. You must have a 1mm spacer between the hub flange and the large sprocket. Without this the lockring bottoms out and even when it seems/is tight it's not applying required force on the cassette (hence wobble). (This maybe why a previous owner has randomly inserted this "wafer-thin, buckled washer on the lock ring".)
Shouldn't be there. The lockring interfaces directly with the smallest sprocket's (serrated) outer face. This results in the 'clicking' (x6) as you tighten the lockring to 40Nm.

Makes perfect sense thanks.
When I got to work this morning, I tried to wobble the cassette and disappointingly (though not surprisingly from your good explanation) the wobble is back.

That might also explain that mystery skinny washer under the lock ring.

At some point I'll just change the cassette for another one, unless the spacers can be bought separately, which I really doubt.

 

[Paulus]

Makes perfect sense thanks.
When I got to work this morning, I tried to wobble the cassette and disappointingly (though not surprisingly from your good explanation) the wobble is back.

That might also explain that mystery skinny washer under the lock ring.

At some point I'll just change the cassette for another one, unless the spacers can be bought separately, which I really doubt.

Spacers can be bought separately.
Your local bike shop, LBS, may have them SJS Cycles do them. Halfords might also have them.
You can get them from Amazon and ebay as long as you know what size your need.

Nearly all spare parts for bikes can be sourced.

 

[richardfm]

Makes perfect sense thanks.
When I got to work this morning, I tried to wobble the cassette and disappointingly (though not surprisingly from your good explanation) the wobble is back.

That might also explain that mystery skinny washer under the lock ring.

At some point I'll just change the cassette for another one, unless the spacers can be bought separately, which I really doubt.

Visit your local bike shop, they should have a spacer. If not try somewhere online like SJS, but the postage will be more than the spacer.

 

[Ming the Merciless]

See 😁

https://www.cyclechat.net/threads/wobbly-cassette-why.294133/post-7066970

 

[roubaixtuesday]

re. the wafer thin washer, IME all cassette locknuts come with that mystery skinny washer. I always assumed it is intended to help prevent the locknut coming loose and deforms under load.

perhaps some locknuts come without?

I can at least assure you it's not been added by a previous owner with the purpose of preventing wobble.

 

[Mazz]

re. the wafer thin washer, IME all cassette locknuts come with that mystery skinny washer. I always assumed it is intended to help prevent the locknut coming loose and deforms under load.

perhaps some locknuts come without?

I can at least assure you it's not been added by a previous owner with the purpose of preventing wobble.

Good to know, cheers for this.
EDIT: Yep, bang on...

 

[Mazz]

Visit your local bike shop, they should have a spacer. If not try somewhere online like SJS, but the postage will be more than the spacer.

I think this is the type of spacer I need.
I've got a 10-speed Shimano 105 CS-5700.

 

[Ajax Bay]

Go to LBS

re. the wafer thin washer, IME all cassette locknuts come with that mystery skinny washer. I always assumed it is intended to help prevent the locknut coming loose and deforms under load.
perhaps some locknuts come without?

Interesting. I have just been to check all my (Shimano) cassettes (part used or new) and none of the lockrings have this skinny washer.
But it's clearly there in the parts diagram.
Given the raison d'etre of the lockring is to err lock to the smallest sprocket, why would you want a washer in there? [Edit: see rationale in later post]
Here's the Tiagra (CS-4600) parts diagram clip:

Further research (BSS): "The "lockring spacer" (so labelled on Shimano Exploded View diagrams) is a very thin metal washer or shim between the lockring [and sprocket] of higher- end cassettes such as XT, Ultegra, and the like." So @roubaixtuesday is a high end user, whereas I am not

 

[Dogtrousers]

re. the wafer thin washer, IME all cassette locknuts come with that mystery skinny washer. I always assumed it is intended to help prevent the locknut coming loose and deforms under load.

perhaps some locknuts come without?

I can at least assure you it's not been added by a previous owner with the purpose of preventing wobble.

I always thought it was to aid assembly. To give a bit of grip as you screwed it on. Now I come to examine it that's a pretty stupid thought, but it has been living in my head for a while.

Edit - I've seen it and I don't use Ultegra components.