cracked rotor on velineon

I have a Feigao 9L on 4s with the CC BEC for gearing I run a Revo 40 tooth spur and RC Monster 16 tooth MOD 1 pinion and I adjust the slipper to control the wheelies if you loosen it too much you lose speed its just something you have to play with. Also if you run on the street and not off road I suggest running the 1/8th scale sedan foams with the 17mm adapters...if you need links let me know