I've noticed on sites like rockauto there are rotors for sale that are
described as quiet.
Supposedly there is a type of iron (called "Gray" iron) that has a
different microstructure that is less prone to high-frequency
brake-squeel noise, but this type of iron is supposedly what most or all
rotors are already made with.
So is this true?
That you can count on your standard white-box, no-name brand of rotors
that might cost you $20 - $30 a rotor is already made using the most
appropriate type of iron, this so-called "Gray" iron, and that anything
labelled as "low-noise" rotors are just throwing that term in to extract
a few more bucks from the price?
(This is not about whether or not a rotor is cross-drilled or slotted,
so let's not take this thread on that tangent).
Also, I've noticed that there are some rotors that appear to be black in
color - not just the edges but the entire rotor. I think these are
described as being zinc plated - presumably the plating gets worn away
on the rotor surface in contact with the pads. Anyone have any
experience with these? Do the areas of the rotor that are black *stay
over time and hence they don't rust?