Ok Example your flying with a plastic spinner and crash down into a concrete runway the plastic spinner would destroy into a million pieces then leaving the crankshaft wide open for attack then the crankshaf hits and it bends the shafter where an aluminum spinner would hit and the aluminum if theres enough force bend the aluminum backing plant and if theres still pressure bend the spinner itself takin pressure off of the crankshaft and leaving it untouched!! so therefore yuh yall may use the for looks but i bet half the crashes yall have had with aluminum spinners its saved yalls motor's