Hi all,

I just got new rotors for my JCW brake kit (Gen1 style) on my R53 MCS.

I had the regular JCW rotors previously and this time I went for the drilled and slotted ones.

After the install (rotors, pads, flush) the car drives and stops fine and I didn't notice any issue or noises. However, when I got home and try to take some pictures, I noticed there are, what looks like "carvings" or "bites" on the edges of my brake disks.

In P1, you can see that the edge of the disks are shaved/carved off by about 2.5" long. These bites are about 1/8" deep but only affect the inner side of the disks. Looking head on at the brake rotors, I don't see anything unusual as the outer surface of the rotors are perfectly rounded. These are seen on the inner surfaces of the disks and are seen on both front and left brakes. This only happened on 1 end of the brake rotors as rest of the rotors are smooth and normal, show in P2.

Can you guys please help explained what this is? Is this a install issue or could this have been manufacturer defects? I'm trying to figure out whether I go back to the guy who sold me the disks or the shop that installed it.

 

Looks like balalcing machiene work to me, part of this manufacturing process. I am sure Todd @ Tce can give us his take.

Alex

 

Looks like possible rubbing from dust cover on inboard side.

 

Hi Alex,

Thanks. I was just a bit worried since I did not notice these markings on previous (non-drilled and slotted) rotor disks.

Another friend also told me its very common on drilled and slotted rotors.

 

I too vote for balancing.

 

Correct. Simply a mill cut for weight removal for balancing needs.