I bought a new set of brake rotors for my car. For an extra $25 for the entire set, I got rotors that are slotted and cross drilled, and nickle plated -- hopefully to prevent rusting on the portions that are not friction surfaces.
What is the correct orientation of the slots?
Obviously, slotted and drilled rotors are directional, but there are no directions included in the packaging on how to identify left and right side rotors. If the vent vanes were curved, then the direction could be easily figured out, but the vents are straight, so the vents themselves do not determine proper orientation.