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Discussion Starter #1
I recently replaced both brake rotors (and pads) on my Cabrio... I upgraded to slotted and drilled rotors after overheating (and blueing) the old ones. The instructions said that the pattern is directional but either way they will work. I initially mounted as directed, installed new (OEM) pads, then test drove. Whirring sound appeared immediately. Kind of like a baseball card in bicycle spokes, faster you go the more noise appears. It was a suggestion by the folks at StopTech (rotor MFG) to flip the pattern and expect the whirring to dissipate after a few hundred miles. 5,000 mile later the noise is still there to the amusement of the neighbors and other pedestrians! The brakes work tip-top otherwise. Has anyone else had this experience? Any suggestions?
 

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I recently replaced both brake rotors (and pads) on my Cabrio... I upgraded to slotted and drilled rotors after overheating (and blueing) the old ones. The instructions said that the pattern is directional but either way they will work. I initially mounted as directed, installed new (OEM) pads, then test drove. Whirring sound appeared immediately. Kind of like a baseball card in bicycle spokes, faster you go the more noise appears. It was a suggestion by the folks at StopTech (rotor MFG) to flip the pattern and expect the whirring to dissipate after a few hundred miles. 5,000 mile later the noise is still there to the amusement of the neighbors and other pedestrians! The brakes work tip-top otherwise. Has anyone else had this experience? Any suggestions?
Sounds to me like friction is occurring between the rotor and pads as your wheels turn. Put the car on jackstands and check for it.
 

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Discussion Starter #3
I did exactly as you had suggested after the upgrade was completed...I did expect drag/friction but there was none. Bled the hyd lines too. Somehow I wonder if it's the pad material, but I haven't changed to semi-metallic or ceramic yet to confirm. Would love to avoid the expense! Cheers!
 

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I did exactly as you had suggested after the upgrade was completed...I did expect drag/friction but there was none. Bled the hyd lines too. Somehow I wonder if it's the pad material, but I haven't changed to semi-metallic or ceramic yet to confirm. Would love to avoid the expense! Cheers!
Did you lubricate your caliper pins during pad installation? A pad may be having some trouble releasing once you start driving.

OR, you might just have a coincidental noise caused by something else entirely.
 

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It's the slotted and drilled rotors making the noise. This is the issue with running racing technology on the street. They don't care about noise on a race car...


Truth is, you shouldn't be running drilled solid rotors on the street anyways. The whole purpose is to de-gas the pad friction area. On a solid rotor, where can the gas go? On a traditional vented rotor, the gassing goes into the middle. I've read several articles where it's stated that drilled solid rotors tend to stress crack around the holes, then they fail unexpectedly. A solid rotor should be dimpled, not drilled through... They will also cause your pads to wear much quicker as well.

If you want to solve your noise, go back to standard rotors...
 

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He's using drilled + slotted rotors, the picture shows that. The whirring noise is still likely the pad contacting the rotor. I agree that it will probably go away in a relatively short period of time.

If it's bad enough, remove the rotor and compare its thickness to the oem thickness requirements to make sure the aftermarkets are within spec. You may need to have them resurfaced, although if they are new and out of spec that is your best opportunity to have the shop you purchased them from to replace them. :nerd:
 

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YES, I run them on Our SMART Car... Love Them... BUT... You will hear them sounding like a Turbine Winding Down (Vary Cool), but will fade away after a 10,000 mile wear-in...
Ebay has the best...
Note: I use Ceramic's

 

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Discussion Starter #8
Sure did... while my car isn't a military jet I've found the same workmanship principles apply whether I'm on the job or on my garage floor! This has been a fun adventure nonetheless!
 

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Discussion Starter #9
Appreciate the information, makes this look less alien! Once the current pads wear away I have yet to go ceramic...looks like that will be next! Cheers!
 

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Discussion Starter #10
The new rotors hardly look used after 5k miles and the thickness between the new rotors and stock rotors (where I have a set of new ones too) are the same thickness. The speed shop I used to buy parts from and have special machining on my old Rally Car seem to think that it's pad material and their thoughts are leaning toward ceramic as they install on their competition road car preparation.
 

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Discussion Starter #11
I appreciate the feedback, truly. However... the way I drive the car isn't exactly grocery hauling or the work commute... I get on it hard, recreationally speaking, and have cooked more than one set of rotors for lack of heat dissipation. By far the move to drilled and slotted rotors has been performance driven. The failure rate the new rotors are labeled with given the load they are designed to be subjected to are higher than the Mean-Time-Between-Failure reliability prediction the engine possesses. Thinking in terms like these, higher performance: adequate heat dissipation with less brake fade, fewer trips to the floor to swap overcooked rotors in exchange for an obnoxious noise...not too bad. The coolest thing this forum has provided me is there is recognition as I'm not the only one who has had the experience... Thanx for the contribution!
 

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I appreciate the feedback, truly. However... the way I drive the car isn't exactly grocery hauling or the work commute... I get on it hard, recreationally speaking, and have cooked more than one set of rotors for lack of heat dissipation. By far the move to drilled and slotted rotors has been performance driven. The failure rate the new rotors are labeled with given the load they are designed to be subjected to are higher than the Mean-Time-Between-Failure reliability prediction the engine possesses. Thinking in terms like these, higher performance: adequate heat dissipation with less brake fade, fewer trips to the floor to swap overcooked rotors in exchange for an obnoxious noise...not too bad. The coolest thing this forum has provided me is there is recognition as I'm not the only one who has had the experience... Thanx for the contribution!
I had a great experience switching oem brakes in another car over to drilled + slotted with zinc plating. Mine gained a little noise at first too, but after a while was well worth the experience.
 
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