vtraudt wrote:
That same hammer hitting upward at the suspension points is also hitting DOWN on the frame along to the ends (pressing down so it does not fly to the moon).
Or looked at the other way: if there were no force on the beam pushing down, they wouldn't need a beam going to the ends.
Note: a beam to only hold static load could actually be tapering down assuming an even weight distribution.
You are right about everything you are saying here. The fact is the frame could taper to nothing at the end if designed that way. (I have seen flat-beds where the crossmembers taper to pretty thin at ends) But what you are talking of doing, replacing the hammer in center with a press on the ends is well outside what the design calls for.
Mounting jack close to the suspension will reduce that problem somewhat. But will still need stabs at the end. And then there is the other force you need to take into consideration. Most trailers, when unhooked, brakes thru wheels/tires keep trailer from moving front/back. When brakes won't work, we chock the wheels. When you jack up to level, all the force causing the trailer to roll will be twisting at top of jack
