the other thing to realize is that with the shackles on the rear, as you hit an obstacle, the tires will move rearward and away from the obstacle, which causes you to bounce on the rock or such, with the shackle on the front, when you hit the obstacle, your tires move forward slightly, and work as if you had bumped it harder, and will resist the truck bouncing as you climb the obstacle more...
though as others said, the clearance is the biggest thing, the geometric thing above should be second to that...
though as others said, the clearance is the biggest thing, the geometric thing above should be second to that...