you got those giant meats for tires too though don't you? its heavy, maybe 15lbs. heres a pic
the 645 is weaker than this servo, i'm pretty sure. i had a jr650 on there. it seemed a little soft, but i think some of that is my servo saver being too weak. i heard some people put a little ca glue on the saver to make it hold better, but it'll still break loose with a strong impact. i may give that a try. its a kimbrogh(sp?).
i also just noticed that this servo is a ds8411sa servo and has some plastic gears. i wonder if i strip them if i can just upgrade to the ds8411 replacement metal gears.