PaJohn

Thinking of getting either a VW Touareg or a 2012 ML350 and will be using it to tow an RV. I know the tow limit is 7,200lbs but I can't find any info on the hitch weight limit with a weight distributing hitch. I figure it should be siginficantly more than the 580lb dead weight limit. Anyone know? Thanks

GregW / Oregon

Information from MBUSA is still sketchy. However, per Carguide Canada detailed specs (http://carguidecanada.ca/vehicles/56...nz-ml350-ml350):

Dead Weight Hitch max trailer weight: 5,000 lb
Dead Weight Hitch max tongue weight: 500 lb
Weight Distributing Hitch max trailer weight: 7,200 lb
Weight Distributing Hitch max tongue weight: 1,080 lb

I would verify these before assuming they are correct.

PaJohn

Thanks Greg. Those numbers are about what I expected. The local dealers have been useless at answering technical questions. I'll try calling MBUSA this morning.

PaJohn

Just got off the phone with MBUSA. They say maximum tongue weight is 575lbs. No info or spec for weight distrubuting hitches. Doesn't make sense to me. VW is doing the same thing with their Touareg. In fact, they specifically state in their manual that WDH's are forbidden. How can they expect you to tow 7,200 lbs with only a 575lb tongue weight?

PaJohn

Just found out that the manual states "load the vehicle so that 8-15% of the trailer weight is on the tongue" or something like that. 7,200 X 15% = 1,080 so that seems to confirm the specs you found. Good news!

Shrdlu

There was some discussion of the weight-distributing hitch ban a while ago in one of the Touareg forums.

Upshot was that WDHs are best suited for ladder frames, such as used by pickup trucks and traditional body-on-frame SUVs. Ladder frames can transfer tongue weight to the forward axle more effectively than a unibody frame, such as used in the Touareg (and by implication other crossover SUVs like the ML).

In the Touareg's case, there was concern that a WDH could overstress the hitch where it attaches to the frame members. On the ML, I imagine that a WDH might freak out the Airmatic self leveling feature.

PaJohn

I'm familair with the discussions on the Touareg forums. As you surmized, the general consensus seems to be that the "ban" was intended for vehicles with the air suspensions and the associated self-leverling system. AFAIK, there have been no reported incidents of hitch failures on the Touareg. I also read somehwere, maybe here, that the earlier ML's did have some hitch issues but those failures were due to faulty welds. As long as MB doesn't forbid WDH's, I guess I can presume they are OK? After all, I don't think you can find a RV dealer that will condone towing a trailer over 5,000 lbs w/o one.

steveopt

I also asked my local dealer if you can use a WD hitch. He said "probably." Great answer...doesn't really help. I can't buy a vehicle based off of "probably". I wonder if you can use the WD hitch if you don't order the air suspension, since it is the air susupension that Land Rover says is the reason you can't use a WD hitch with an LR4.