Air suspension is nice, because crank up psi, level to slight up on rear. Very little wieght if at all is then taken off the front. If anything, added to the front.
Scooby,
My IHC almost always has weight added to FA with a load. Typically 5900-6000 empty front. 5600-5900 rear depending on if diesel tank has 5 or 50 gals in it.
Ad 14000 lb getting me to registered 26k. I'm at 7509-8000 on front, rear in the 17-18.5k realm. Generally 8k and 18k Fr vs Rear. About 2000 added to front, 12000 to rear. In par with body builder specs of 85-15% to 90-10% rear to front wieght distribution.
Of course final weights depend on what I'm hauling, ie rock will usually load all forward of rear axle. So bussed to from axle. If light wieght like bar/sawdust etc, a bit more to rear, as bed is filled to 15 CYD capacity vs 4-5 yds of rock.
At the end, one can not trust one set of numbers, formulas to guess front to rear distribution of wieght, as other factors come into play, ie actual weight ratings of springs, how literal stiff they are, rear overhang, CA length, cab configuration, how high the rear is frame wise, vs does the frame go tail down loaded vs level or up,
Being as I do not know the multipliers to figure that out, other than thru experience, I can tell you it can vary and depend what a given weight load will do to a given chassis truck.
Just like one person that lists the weight off of front axle is the percentage of rear overhang divide by WB. That formula is too high to a point, the correct at one point. Then actual is higher than formula states in higher hitch wieghts for a ball mount setup. There is no factor for rear suspension settling, or the spring rating. Good ball park, not a formula I would want to place my life on it being correct.
Marty