Shimano disc rotor lockrings… Are they interchangeable?

Are all Shimano lockrings interchangeable? I know there are steel/aluminium and internal/external spline and some with Shimano printed in white and some plain but can any of them be used on any rotor?

The Shimano exploded views for diferent rotors give different part numbers but I have three different types in my parts bin and none of them have a part number on them so how do I know which is which? Or, doesn’t it matter?

I dont think it matters, I have mixed them up or replaced internal for external spline and nothing has fallen off.

They can be used with any rotor but, what you have to be careful of, is whether they will work with your axle and or frame.
There are tool access issues with the traditional lockring tools, on some axles, and the thickness of some of the thru-axle compatible lockrings can cause clearance issue on the caliper bolt bosses on certain forks

Yeah, lock ring thickness varies and can cause clearance issues.

I know the HB20 is the same as the prime 15/20 and the m8010 all of which fit most everything.

I guess I’ll just have to see what fits then when the wheels turn up. Shimano hubs though so that should… should… make things easier…

I have about 6 of the shimano ones sat here (the centerlock lockring), across sizes, all look the same, i use the DT ones on the wheels as i have DT hubs, they look the same as well in terms of dimensions, i’m going to guess they’re like for like, DT offer them with the hubs, so are rotor agnostic, which would make me think shimano are as well, unless there’s something weird about the rotor, like vented or thicker?

I’ve got Shimano rotors too so it will be OK it seems. I would like to know what the Shimano part number is for internal splined Aluminium ones though, so I can buy two the same – if anyone happens to know…….?

UPDATE: I think it might be Y8K198010 actually.