Originally Posted by rostam
This is not about "setup" (whatever that means). There is not a single unibody vehicle in the market with a 800# or more hitch rating. And most ban the use of WDH. 1000# hitches are readily available. Why wouldn't the manufacturers put them on their unibody vehicles? Well, for a substantial hitch, you need a frame to mount the hitch to. You also need a frame to do substantial weight distribution.
Germans seem to have a different scheme for rating their hitches.
In every one I have seen (Audi, M-B, VW, M-B) the tongue weight rating is exactly 8% of the trailer weight.
And it may be that since WDH's are a recent arrival in Europe, they just haven't tested or certified their hitches for Weight Distribution. Everything is so regulated over there - maybe their lawyers advise never to use WDH in a sentence!
They also construct their trailers a lot differently, with few dual axles.
I think one of the components of their gross weight rating is the ability to accelerate the load, not TV axle capacity.
I have given up on trying to guess how it all comes together, and rely on the Gross Axle Weight Ratings, some work at the scales, and math to predict suitability. And loading.
As for the need for a frame, if that were the only qualification for load-carrying, we'd see 747's raining from the skies.