I’m going to have a look today!Oh I see your other thread now.
The newer 11, 12 and 13 speed (not tooth) cassette lockrings are a bit thinner than the old 8/9/10 counterparts, yes.
However it would be a shame not to use that particular lockring because it really belongs with that cassette;
they are both that lovely blue anodised colour with white highlights.
So the lockring looks correct to me.
It is a 12T small sprocket after all.
If you use an 11T lockring on a 12T cog (which is not recommended), you will/may get this kind of effect, where it is recessed:
(but nobody does this)
You will gain a few mm once you tighten the cassette.
But you either need to get the spacers and/or overlock nut dimension correct.
Are you sure there is no spacer behind the cassette?
Ah I thought you meant thicknessibbz, from the initial look it looked like the diameter was a touch to small for the 12T, but you then mentioned it was not tightened.
Steel ends are thinner because they are steel compared to a lot of the Alu ones that need the bulk to stop them cracking, often with a tapered look. Not all, mainly because they can make them thinner.
I do have some thinner Alu ones from BiTD but they tend to be not a strong.
back to the other topic and get some hub pictures up etc..
I did say both.Ah I thought you meant thickness
Diameter is fine as far as I can see. But the problem lies as @synchronicity said
What does bind mean?I did say both.
Thickness was when it looked like it would bind. Problem with a phone is you can't see the detail.