GMC "Leaf Springs" Why ?

[barraza]

There was no love lost between Chevy and GMC at the time. They considered them selves in competition just as much as with Ford or Chrysler. It was a different philosophy. Coils do definitely ride better, due to less friction in the system. A coil also locates the axle better than leafs. BUT , leafs are much easier to engineer a variable load rate spring. A leaf can theoretically have a softer spring rate at light loads and a much heavier rate at heavy loads, that is why most leaf systems have many leaves. Most trucks still use leaves for this exact reason.

Leaves also have a natural anti sway effect due to the twist the spring must have as the truck leans. With a coil, a sway bar must be used to have the same effect.

And the above answer about wood beds is correct. A long time ago, small farmers typically hauled livestock to market in the bed of their truck. Much better footing on wood.