[Mr. Adventure]

I've been working on calculations to get to an engineering analysis of the WDH numbers, and I still have a ways to go before I have the illustrations needed to make it more understandable. I'll try to get this done in a week or two, and I will post it here when I do.

Meanwhile, in round numbers, without a WDH: A 500# trailer tongue weight will add something like 700# to the rear axle of the tow vehicle, and subtract the excess from the front axle. Your tow vehicle stopping and steering traction will be reduced by approximately the front axle weight reduction percentage. The rear mounting bolts of the trailer hitch receiver will each carry almost 2 times the tongue weight because of the lever advantage at the hitch ball (in addition to what happens on the bumps). The axle effects are easily checked on the truck scale and will come out the same with or without air bags.

With a WDH: the front axle unloading goes away, the tongue load that otherwise would go to the rear axle is reduced by the loads that get moved to the front axle and the trailer axle, and the loads on the rear hitch receiver bolts are about zero (except on the bumps, of course). The front bolts on the hitch receiver are loaded with respectable numbers, but there are four of them to share it and no single one of them is more than the tongue weight.

A WDH is mandatory for most of us.