Originally posted by collector fred:
i have a question why do people cut the frame when they put a box and hoist on there should be enough room to tilt the box without cutting the frame.
You cut the frame just behind the pivot to allow the rear of the bed to drop closer to the ground and to limit how high the front of the bed must go. Cutting the frame at the pivot also means you don't have to raise the pivot.
A heavily loaded truck with the bed in the air can tip and fall. The lower you keep the load the less likely the truck is to become unstable.
Also in many cases, you have better control of where your load goes if the load is coming off the truck nearer the ground.
There may be other reasons, but these are the ones that come to mind. I've never put a dump bed on a truck and certainly can't claim to know all.
But twenty-some years ago I was a mechanic for a small trucking firm with a bunch of little trucks. I remember that the beds all pivotted just behind the rear axle and the frames were cut at that point.