Originally Posted by billdelong

just to clarify, I meant the polarity from the battery to the ESC is what can't be reversed without risk of damaging the ESC... if you reverse the polarity from ESC to motor, it will simply change the direction that motor spins, that's no big deal, typically you can either reverse the direction on the radio or swap the wires between the ESC and motor to get it move in the direction you would like.