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Discussion Starter #1 (Edited)
Does anyone know why the OEM style BMW pads have multiple grooves cut in the pads?



I purchased and installed Carbone Lorraine pads which had a single groove down the center of each pad.



While the braking is fine and without squealing, I do hear a 'whine' or 'hum' similar to a decelerating turbine when I brake (actually its more like a 'zzzzzzzzz' sound). Its definitely coming from the front brakes. I think it has to do with the drilled front rotors and the single slot in the pads.

My theory is that the OEM pads have the multiple groves cut in them to address this very complaint. If not, why are the additional grooves there?

Thoughts? Comments?
 

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Old Slow Guy in A Fast Car
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Cooling of the Pad/Rotor. That is why high performance rotors are drilled & slotted.
 

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Discussion Starter #4
katnapinn said:
Cooling of the Pad/Rotor. That is why high performance rotors are drilled & slotted.

That explains why the rotors are drilled. It has nothing to do with why the pads have slots on them.

The interesting thing is the grooves are not symmetrical on the length of the pad. This leads me to believe that they are designed to change the harmonics of the drilled holes in the rotor sliding by.
 

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The groove is there so people will ask questions!

Most rotors have groves and or holes to conquer the off gassing and cooling issues associated with braking. I have seen friction pads in various applications with this done for the same purpose.

However, in this case the groove in these pads is simply for you to know when to replace them again. When the grove is no longer visible its time to replace them.

Bonded pads I believe can run as low as 1/8th or 1/16th of an inch...you can use a drill as a gauge to compare the remainder of the pad beyond your groove to the steel backing. Then you can tell us all what you found.....

Scott
 
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