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I agree, drilled rotor are not for the street. Showed a guy at cars and coffee how his ebay drilled rotors were cracking from hole to hole. Scary.

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That's why you should never buy cheap Chinese rotors off eBag. You get what you deserve cheaping out on rotors. There have been thousands of good drilled rotors raced for decades with great results. The good rotors have the holes counter sunk drilled to relieve the sharp edges which reduces the cracks.The iron used is important as well. Solid rotors crack too. You can see little cracks on most any type of rotor that's been heated red hot and then squeezed hard during a race. The later slotted rotors will have cracks as well after a race. Wilwood would not sell drilled rotors if they were no good. I've never had a pad glaze up on a drilled or slotted rotor, solid rotors glaze up much easier because the lack of pad surface "wiping" that takes place due to the holes or slots. The pads don't last as long, but if you're worried about pad life this is the wrong forum.

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It depends on the quality of the material the rotor is made with. I've seen hundreds of circle track rotors glowing orange that are drilled and they endure pretty good.

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... Wilwood would not sell drilled rotors if they were no good. .....

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... Wilwood would not sell drilled rotors if they were no good. .....

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Sure they will. They're in the business of selling brake parts. Enough people ask for them and they'll sell them. Actually, having worked for them at that time that is exactly what happened. They didn't sell them because it was unnecessary, but they got enough "tuners" asking for them that they saw a market, did some R&D and started offering drilled rotors.

The time for drilled rotors has passed. The original reason for the holes was to give the gasses generated from the friction material a place to go rather than creating a barrier between the pad and the rotor.
Modern friction materials do not out-gas like older pads (Ferodo DS11's anyone?).

The holes also had an unexpected side-benefit in that pads that really needed to be up to temp to work well tended to warm up slightly faster with drilled rotors. It was subtle, but with a good and consistent driver you could see it in the lap times.

Chamfering the holes results in holes that now have two sharp edges per side rather than one. Notice that the wilwood rotors are radiused. That isn't an accident.

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I recently got the missing brake rotor from Dr. Diff the other week. The front rotors from the Stage 4 kit I got have internal vanes that are vertical while these new rotors are curved
The weird thing is they are both curved in the same direction! .... Is it ideal? No, but I have no problems running like this because I doubt I'll get into high enough temps to max out my...

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I noticed the same thing with my kit. Vanes are same direction but drilled holes/slots are different... when they crack I'll switch them out to slotted. Car gets very few miles, so I can wait, not a show stopper.

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On a side note, these suckers are heavy!
They weigh more than my wheels!

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