21.1 is the ROAR minimum for IR of the stator, my Trinity Revtech Maxzilla is 21.4/21.4/21.3 and I race with a guy who owns a Big Blue Bad @$$ which is a Big blue can and 13mm rotor, and i pull him in RPM, but he gets me in torque because of the rotor. The BBA is only legal in outlaw and mod classes, but at our club races they dont tech motors.