BigEd

which goes back to a couple-day-old discussion: pressed or welded? So, they're pressed?

RKA

I've never seen them...but they aren't welded, that's for certain.

Carson (K03x2)

Usually when you replace the rotors, its a good idea to get new ABS sensor rings to put on, as removing them from the old rotors opens them up a bit and they don't fit on like they used to....the possibility exists they might get loose and spin or come off entirely.

And yes, I have seen this happen to other technicians I have worked with over the years. Thankfully I have managed to avoid that embarassment.

BigEd

I know the suspension has been worked on, so they migh have replaced the knuckle, re-installing the ABS ring which later slipped triggering a code.
Makes sense now.

Carson (K03x2)

Most models now use a ring permanently installed on the outer CV joint to measure wheel speed.