I do not know the exact math but the WDH helps to take the tongue weight and distribute evenly so the full tongue weight does not rest on the rear bumper. Granted, is not a magical device. What people need to understand is that Pounds (Lbs) is not a measurement of weight, is force. Kilograms is a meaurement of mass. The WDH distribute the force between the TV and the TT. The full force is not 100% applied on the TV, part of that force in lame terms, is pushed back to the travel trailer. Some like... tongue weight 500 lbs, with WDH, 300 Lbs (150 lbs per axle) on TV and 200 lbs on TT. Again, not sure of the whole math calculation but I can say for sure, the entire tongue force is not applied to the TV.
2016 Rockwood 2306
2016 Chevy Colorado Z82 / 2009 Pontiac G8 GT