brake rotors

[Hughdemann]

I'm going to replace the pads in my front brakes, and while measuring the rotor thickness, I noticed an arrow showing direction. I looked in the parts list, and the rotors have a left and right application. Does anyone know why? The offset is the same, the size is the same, the only difference I saw was the orientation of the holes drilled in the rotors.

Hugh :???:

[ezride]

Just a guess, but where the rotor bolts up the machining is critical for plane and flatness on the side that contacts the wheel hub, but not on the bolthead side. Maybe they only machine to these tolerances on the one side?