Apologies for the delay in response. We have been traveling (with trailer) for just over a week - and continuing on for another 10 days or so. I will provide the model number and make of the weight distribution rated aftermarket hitch (made for Atlas) here. We have not had very good internet recently - until today.
I have been mounting the trailer to the aftermarket hitch now since installed. No problems at all. I have noticed that the vehicle handles slightly different - not bad or good, just slightly different - but not by much. The side-to-side movement of the trailer does feel more rigid now though. I am not sure if this is a function of the new shank I installed on the WDH, or the fact that hitch is now mounted below the frame evenly, instead of the bumper (OEM). With the exception of improved side-to-side stability - nothing has changed with how I, or how it tows.
I did NOT buy the Curt version of the aftermarket hitch as it is not rated for weight distribution - and you can tell from the back of the receiver tube it does not have a reinforced rear receiver tube vertical plate extension - connecting back to the hitch bar. You can tell the difference when you compare it to the Draw-Title version that IS rated for WDH - and has the extra steel plate behind the receiver tube to accommodate the flex and forces of a WDH. I imagine this is what VW refers to when it says "the vehicle is not designed to be used with a weight equalizing hitch". Behind the OEM receiver tube, there is no such reinforcements either. Coupled with the fact that the bolts from the hitch tube go into the frame differently - I am going with the idea that this is what they are referencing.
After researching the Draw-Tite hitch and hitch parts, I am working with the idea (another assumption) that the bolts and nuts are rated for literally 10s of thousands of lbs of shear strength - I believe they use Grade 5 bolts (silver bolt assemblies). You can do the math on that one times 4 (x4). I would imagine the bolts would stay in place with part of the hitch attached at that bolt and nut points, and the hitch would have to fail elsewhere if it ever did. They go in vertically - directly into the frame - four of them. I keep inspecting the bolts and hitch itself almost after each trailering day and they aren't going anywhere. I am no engineer - but I can tell you from experience the hitch has not moved, bent or budged a millimeter. I have driven already miles on smooth highway roads, and miles of forest roads with large pot holes.
This past week (actually last week) - the campground that we were scheduled for required us to bring a full load of water in prior to setting up. That added an extra 300 - 400 lbs near the front end. My tongue weight of course rose proportionately. The Draw-Tite WDH is rated for 900 lbs tongue, so I was less worried about the hitch, and more concerned with the rear axle and squat. You can tell the Atlas dropped another inch. But that's about it. I am guessing that my tongue weight at that point was about 550-575 lbs. I still need to invest in a tongue scale. The Atlas was probably towing at that point anywhere between 5,000 and 5,400 lbs. At that point I could tell the camper was behind me when hitting hills. I drove about 15 miles with the water in the mountains. At slows speeds you can't tell, however, at higher speeds going up hill we would slow down a bit more, than with an empty water tank. I guess this is understandable and to be expected. I would not want to drive much more than that with a full water tank, at that approximate towing weight for longer. So in short, the Atlas was working harder to maintain speeds with that kind of load.
Also almost forgot to add - the aftermarket hitch does add about 50 lbs of weight against the Atlas payload if you are tracking that.
Here are the parts:
Large shank to raise and level the trailer about to where the OEM receiver would sit. (Install WDH head using highest holes - this one works with a Curt WDH - probably would work with other weight distribution hitches - you would have to confirm)
Weight distribution rated aftermarket hitch made for Atlas.
