Originally Posted by GreenTourer
Ah, I see...........I think what you call rotors in the U.S. is we call vented and drilled discs in the UK, thus my confusion. Never heard them called that before.
...vented points to the area in between the inside disc surface (where the inner pads touch) of the rotor and the outside (where the outer pads touch) surface.
If you stand a rotor on end and look at it as if it were a "blade", the vented area is the space in between the inner and outer surfaces.
Non-drilled rotors can be vented (space in between surfaces with vanes to guide the air through) or non-vented (solid). Either of these then can be cross-drilled or slotted.
That is all...