found that why the plastic spur was wearing was the plastic motor mount flexes on throttle/brake. the steel spur was a gift and have been running it for a couple months now with no problems, my bench test show that the steel spur only heats up gradually as the heat from motor is transferring to the pinion then to the spur.
definitely going to look into the derlin spur to cut down on rotating mass now that i have the king headz motor mount which keeps the motor from flexing.