I have run the same set of rotors for two seasons but had to change at the ARRC. I agree with Jake that pads are probably the reason as I also run 3" brake ducts to the center of the rotors for cooling. This was the 4-5th race on these pads and I had a 3/16" crack on one side of the LF rotor. Also the first time I had tried this brand pad and the first rotor I have cracked. CB