Nictrix wrote: ↑Fri Jan 05, 2018 6:05 pmI really cant see it being wear indicators for a few reasons.
The amount of material taken off the disc to reach that level would be huge.
When the disc wears it never wears at the edges so it would be difficult to see if the disc had reached these marks.
If it was wear marks surely they would have them the same sort of size equally spaced around the disc.
It isn't a wear indicator at all. It IS for balancing the disc after its been machined.
The brake pads don't sweep that near to the edge and therefore even a well worn disc would still have those machined notches intact, so that the balance doesn't change as the disc wears, it assumess that a disc wears evenly, which most do unless there is an issue with pads/calipers. THAT is why they physically stamp the min thickness on the edge, because the pads don't wear the edge..