I am weird when it comes to crank flips, I can do them, but only left footed, this is strange as I am right foot forward I am pretty comfotable doing them though, dont need to watch them or anything and can just about do them on either my front or back wheel. I recken I do them left footed as that foot is used to scooping the pedal up from bunnyhoips and so on, I just do the same movment with my foot except kinda upward, hey presto a crank flip.