testing wheel clearances in CAD with larger tires

front and rear pivot mounts with rigid center mount

center mounting…accommodates a little flex perpendicular to the truck centerline, e.g. as the frame twists the left chassis rail goes up at the front end and down at the back, while the right rail turns the other way…allows chassis flex about its axis, but is rigid up and down, fore and aft, to support the camper.

mounting plate for the center rigid mount

twist test

front and rear pivoting crossmembers…modified to allow a little more deflection

clearance to the cab