a4944

Hi All,
I have OEM solid Zimmerman front rotors and PF97 pads. The front rotors have many spider (surface) cracks all the way around (like a web). I ran an event on them and they were fine, still have the cracks but they performed fine. The rotors are thick enough. Should I have them resurfaced? Will the surface cracks cause any problems?

Thanks,
Mark

ltc

From what I have been told, the rotors can be used as long as the cracks do NOT connect adjacent holes.

a4944

Thanks, they are not cross-drilled so that's not a problem. They are just the basic vented solid rotors. I can't feel the scratches so I think I'm OK.

Thanks,
Mark

DER951

One rule I've heard (but can't verify) is if your fingernail catches in the crack, replace the rotor.

Bill Gregory

Can you see a bluish hue on the rotors? Sounds like heat cracks forming, is your rotor cooling up-to-snuff?

Claus Groth

I received used 928S4 slotted rotors with upgrade calipers. There were spider cracks all over them when received. I have used them for perhaps 15 weekends and after the last event found a radial crack that is about 1-1/2" long and projects throught the outer edge. They lasted a long time but, of course, have now been retired. I felt perfectly safe with the spider cracks and checked them after each event.

Hope this helps.