It's gotta have a shoulder that drops into the rotor center bore.AT 7:18 how do they center the blank over the rotor?
But it doesn't seem to me they're critical about that center bore diameter, so I'm thinking the bolt pattern isn't that concentric. Plus their method of dropping in a keeper pin after drilling the first hole doesn't make for a super accurate bolt pattern unless that pin is a tight slip fit.
This could allow the rotor to spin, well, eccentric once actually mounted on a vehicle.
I'm really curious if these work on anything above, say, 40mph.