drilled or dimpled rotors
Thread Starter
Instructor
Joined: May 2009
Posts: 105
Likes: 3
From: Kimberly WI
drilled or dimpled rotors
This winter I decided to upgrade my brakes so I purchased a set of front and rear EBS slotted and dimpled rotors (front HD 13") with Red Stuff Ceramic pads. My question for anyone who has used dimpled rotors before. Is the popping sound while driving because the air is being trapped inside of the dimple as the rotor rotates ? The combination of the popping sound and the ceramic pads scraping against the rotors makes enough outside noise that I'm thinking of selling everything and switching to drilled rotors and semi pads. Don't get me wrong, the quality and stopping power are great, but I don't use my car for anything more then cruising. I may have purchased a set-up that is way over its intended purpose. Again just looking for confirmation to my set-up. Thanks
Pro
Joined: May 2007
Posts: 544
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From: Olympia WA
I have used dimpled rotors on my Porsche before and I have never heard the popping you are talking about.
But I have never used ceramic pads with them either. Could be the combo. I usually used Axxis Metal Masters on the 911.
I did do a quick search (Google) and came across quite a few threads on it and it seems like it is hit and miss. But most folks reporting issues are using ceramic pads.
Personally I only use slotted rotors now unless they are Brembo's with the cast holes (not drilled).
You could try chamfering the edges of the pads to help (if they are not already). Also, you could cut 2 vertical slots across the face of the pad to relieve the air.
The noise should lessen as the rotors wear.
But I have never used ceramic pads with them either. Could be the combo. I usually used Axxis Metal Masters on the 911.
I did do a quick search (Google) and came across quite a few threads on it and it seems like it is hit and miss. But most folks reporting issues are using ceramic pads.
Personally I only use slotted rotors now unless they are Brembo's with the cast holes (not drilled).
You could try chamfering the edges of the pads to help (if they are not already). Also, you could cut 2 vertical slots across the face of the pad to relieve the air.
The noise should lessen as the rotors wear.
Pro
Joined: Jul 2006
Posts: 635
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I've read the dimpled rotors handle heat a lot better. That the drilled rotors can crack and warp under racing conditions where heat is high. I know you are not interested in racing but dimpled is most likely better on the street for heat also. I'd try changing the brake pads first, maybe try a set of hawk hps pads. That's what a lot of guys use on corvettes. Good Luck Tim
Former Vendor
Joined: Oct 2009
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St. Jude Donor '11-'12-'13
Dimpled does nothing for heat dispersion. Drilled rotors shed heat better due to the increase airflow through the casting. As you noted though they are not recommended for road racing applications.
Brembo doesn't cast holes in any of their rotors, it's not possible.
The issues you are having are most likely due to the red stuff pads you are running, in the independent testing I have seen, EBC pads in general have friction characteristics that are ALL over the place.
Brembo doesn't cast holes in any of their rotors, it's not possible.
The issues you are having are most likely due to the red stuff pads you are running, in the independent testing I have seen, EBC pads in general have friction characteristics that are ALL over the place.
Pro
Joined: May 2007
Posts: 544
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From: Olympia WA
Sorry there BrakeMotive. Brembo does indeed cast some rotors with holes in them.
These include the Porsche 930 Turbo, 964 Turbo and 993 Turbo rotors. I also believe that Movit has cast holes in some of their rotors for Porsche applications. They source some of their rotors from Brembo
Now it is true that Brembo does drill many of their rotors, but they do cast the holes in some.
I am curious as to why it is impossible to cast the holes?
See the attached pic of a Brembo rotor with cast holes. You can see the rough cast area inside the hole just below the machined chamfered edge.
These include the Porsche 930 Turbo, 964 Turbo and 993 Turbo rotors. I also believe that Movit has cast holes in some of their rotors for Porsche applications. They source some of their rotors from Brembo
Now it is true that Brembo does drill many of their rotors, but they do cast the holes in some.
I am curious as to why it is impossible to cast the holes?
See the attached pic of a Brembo rotor with cast holes. You can see the rough cast area inside the hole just below the machined chamfered edge.
Last edited by Shock96; Jun 21, 2011 at 12:40 AM.
Thread Starter
Instructor
Joined: May 2009
Posts: 105
Likes: 3
From: Kimberly WI
I finally figured it out. After switching one of the front side rotors back to the original rotor, the noise stopped completely. I then toke the other dimpled rotor sprayed water on the back side, spun it by hand and the noise was even more pronounced then when it was dry. I understand that others have used these type of dimpled rotors and no noise what so ever, but in my case, they are just to loud for me. Now to see if I can sell them and go back to drilled. Thanks again for your comments.
