I appreciate everyone's concern. No worries. I believe there is more to the LR4 than meets the eye, though. It has some excellent electronic sway control technology. As for the wheel base it may not be great but at 113.6" on a 190" body it is better than a Toyota Land Cruiser at 112.2" on a 194" body. And the Land Cruiser which has a towing rating of 8,200 lbs. (Yes, it has a solid rear axle but it also sits up higher in normal operation.) The Land Rover has a better departure angle (which can bring the trailer closer to the rear axle depending on how the hitch is mounted.) The Land Cruiser is certainly not a long wheel base either but it has been used effectively for a lot of towing chores. Some would argue the LR4 air suspension is a disadvantage. Others suggest the automatic leveling is an advantage. Yet there was a lot of opinion out there. I needed to find someone who had experience. Lots of guys pulling heavy boats near the max of 7700 lbs and having no issues. But the hitch weight with boats is much less. I needed to find someone who had pulled a travel trailer that was at or heavier than what I want to do.
And, yes, there is actually hope! ;-) But more on that in a moment.
ebemis, as I have been researching this it appears the reason for the 550 lbs hitch weight limit is actually somewhat murky. There was one posting of some who claimed to use a WDH to pull an Airstream and something about the hitch breaking and Land Rover wouldn't cover it under warranty. Is it possible this person was also using the "stock", plug in, hitch receiver with a WDH. Anyway, something about the shifting back and forth causing that receiver to break off. Many suspect that LR is more concerned about how well the "plug and play" receiver mechanism will work.
But I have been in contact today with two people who pull larger loads.
One actually has been pulling a Shamrock 23IKSS for a year. Same specs as the Roo. They have had no issues. Air suspension works great. BUT, they installed a different hitch receiver directly to the frame with a much higher hitch rate. (And, yes, they keep the GVW and Gross Axel Weights (front and rear) in mind. (See the numbers above.)
The other was more impressive but he did more significant work. He has been pulling an Airstream Eddie Bauer 27' rated at 735 lbs on the hitch before (though loaded he has it at 885 lbs), a total dry weight of 5,900 with a carrying capacity of 1800 lbs. When they actually did a weigh in the total trailer weight was 7,150 and the hitch weight was over 1,000 lbs. But to make that work he had a Hensley Arrow load balancing hitch installed and a Hensley Tru Gold brake controller. (He had to change out his oversized spare to make the hitch fit.) So, again, it appears to be possible to make load balancing hitches work. But the key here is that this guy used someone who had a lot of expertise in making different combinations work and had done this a number of times before. (He said he does get the trailer axles serviced every hear. He also runs a TPMS system on each trailer tire to keep an eye on them.) And, no, I cannot afford the Airstream and I probably don't want to go full out on the Hensley stuff. But I will definitely be looking at a hitch and likely one that will better handle heavier loads. I will not use the factory plug and play hitch. (I bought it on eBay anyway so no big loss.) I just need to see how the permanent hitch effects my departure angles and ground clearance in the center but the latter should be no worse than what I have with my spare underneath (9.6" normal, 11.6" off road.)
BTW, if you want to see something interesting, check out this website. Not saying at all that I am going to go there but it is interesting what is possible. I was pointed to this site by a couple of different people.
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