overkillFFF
+1y
One of the main reasons frame flex is comfort for the driver. When you have a half ton truck with leaf spring suspension, it''s not the softest ride. If the frame is flexing, it takes alot of the roughness out of the ride. Seth is right, an import has a fully boxed, welded frame. In the case of older Nissan's, there was internal zigzags inside the frams for extra stiffness. If your running a full air suspension set up correctly, your bags will compensate for having very little twist. If the frame is fully welded, fishplated and gusseted, you will never crack or have failure if done properly. I see beautiful frames that have all the joints ground down and smoothed out. It looks awesome, but in reality, you've ground away half the strength of each and every weld, no matter how much you bevelled each joint. You must fish plate, it's the best way to retain strength.