Originally Posted by Elk
Both dimpled and drilled rotors offer no performance advantage over plain rotors; they are there for looks alone. Dimpled have the advantage of cracking less. Drilled rotors quickly develop stress cracks with harder use.
I agree with some of that, but those angled slots do have a purpose and added benefit.
They vent gas build up during hard use allowing the pad to better maintain contact with the rotor.
Also, the edges provide a "shaving" effect where pad material is removed by the slot edges and that helps keep the rotor surface cleaner to help pad to rotor surface mating for better and more consistent braking.
And, those added edges provide an additional friction surface for harder bite.
The negative is that pad material collects in those grooves over time, and that will lead to not looking so great later in life. But, just keep'em clean.
Also, the larger rotor size helps to keep the rotors/brakes color, and that's very beneficial on hard canyon runs, and especially track use.