stevensa

Hey All,

I have an 02 z06 with stock calipers, Performance AFX two piece rotors and Carbotech xp10 pads. I recently put on a new set of pads and after some time on the road course (about an hour of hard use) I began to get a deep HUMMMMMMMM from the brakes that you could feel through the car. The braking feel and performance did not change at all and I ran for about an hour longer with it like this with no issue. The feeling was worse when the brakes were cold and got much lighter when up to temp.

I have had this happen a few times before when I swap pads from side to side and it goes away. I am thinking that the slight taper in the rotor from the pads wearing on them weird over time, the inherent pad taper, and the rotor slot wear is causing this. This only happens when braking hard, and there is no odd feeling when braking lightly (normal street use).

My question is, does anyone else ever have this happen? Should I be concerned or just roll with it? I am pretty sure that after I swap pads from side to side before the next event this will go away after a bit of driving as usual, but I just wanted to see what everyone thought.

Below is a picture of my rotors, as you can see the outside edge of the slots is more worn than the inside.

Thanks in advance

MySR71

I ran Carbotech XP10's (front) and XP8 (rear) with a front and rear StopTech BBK. I know just what you are talking about with regards to the HUMMmmmmmm sound. It seemed to be more pronounced after pushing the car a bit harder. To me, braking performance seemed unaltered. The fronts (I don't recall the rears) did seem to have what looked like smeared pad material on the rotor face. I recall being able to feel the roughness when braking hard. Again, this didn't seem to be impacting braking performance although I began to wonder if I was overheating the pads. I was on street tires at the time.

stevensa

Interesting, did you get any feel in the pedal or wheel from the hum? I get a very light feel which can best be described as a similar sensation to feeling the sound waves of a sub woofer through a thick wall. At first I thought maybe I was having some other issue, but the car felt normal at speed when not braking and otherwise performed the same.

kmagvette

XP10s and XP8s are light-ish pads for hard track use. Pad smear will make a humm or whirring noise that changes pitch as you slow down. The smear will come off after you drive on the street for a while with the brakes cold...or hit the disks with an orbital sander.

If you do have smear and you are not leaving the nannies turned on, then it is time for XP12's up front and XP10 out back.

Rag Top

I get that hum too. I just thought my Vette was just happy to be at the track. I only worry when the peddle gets soft.

AU N EGL

that may be the slots scraping the pads making the humm noise

stevensa

No nannies, I may be getting a bit of smear but this particular track is a smaller tighter course which doesnt really give the brakes a chance to cool. If the problem persists I may look into the next pad up but the 10's still seem to have a good bit of braking power, at least for street tires that is.

Thats what I am thinking

mountainbiker2

I have the same brand rotors front and back and have the "hum" noise. Without any interior mines real loud.

Steve A.

stevensa

Can you feel it at all coming through the steering/suspension/floor under hard braking? I get the hum and that deep bass feeling like I described above, esp when going back out on cold brakes.

MySR71

Yes, I could feel it through the car. My rotors are slotted too.

mountainbiker2

No feeling coming through. Just a lot of noise.