Originally Posted by
Russ Roth
Does the other rotor have the same coloration? Might have been a result of the final heat treatment of the rotor or just meant to add an effect. It is unlikely to have this develop from a slight rub that's so small it doesn't affect the effort needed to maintain speed. So either the rub is worse than you're claiming or something else did it and you need to watch how much you're dragging the brake on steep descents.
my comment on the rub was suggesting that since there is a slight misalignment, maybe when braking only the inner part of the rotor is engaged or maybe that part engages first. I don’t think the constant minor rubbing generated the heat. Also, my hill is very steep and very long, I cannot reasonably use the front brake less than I am doing.