I've noticed that my rotors in the front are "dished" out somewhat. Not warped. Hollowed out. Is that normal? Do I need new rotors? I've got 27k miles.
Still lovin the GP.

Thanks

 

Yes, tends to happen with time. To tell if they are worn out you need to measure the thickness with a micrometer. You measure at several locations around the disc. The minimum thickness is stamped on the inside of the rotor. I forget what it is, have it written down in my workshop.

The discs are quite durable, with racing I have gone through 2 sets of pads for each change of disc. So I would be very surprised if yours are worn out at 27k miles

 

When you said dished , was thinking the back of the front GP2 rotor have the dished look like the front JCW 4 pot brakes, right near the vanes. Been running them with our GP2 BBK retrofit kit on the R58 JCW and tracked and they have been fantastic.