Does anybody know what the name of this feature is?
This is the back side of a hyperglide hub where the hub body engages the wheel hub. I’m trying to upgrade to 10 speed. Original on the left, new part on the right. There’s 10 teeth on the old one and 15 on the new one.
New one obviously won’t fit due to the difference in the number of teeth, but adding 10 tooth to my searches doesn’t bring up anything helpful


Would that not net a hub that is then wider in total, and no longer a size that fits the frame?
AFAIK, the cassette mount is not the only thing that changes when going from one size to another.
The new part looks wider, even if if you could install it, you wouldn’t get something that works.
It’s only a 4-5 mm difference, so it fits fine in the rear triangle with the stock axle even with the added 3mm from the new part not meshing correctly (10t vs 15t)
Ok, but that still leaves the fact this isn’t supposed to to work.
You’re combining parts even the manufacturer will never have considered would be used together.
The internal ratcheting mechanism and how it is mounted isn’t a standard you can look up compatible parts for the way cassetes or bottom brackets are.