When we first started looking seriously into getting a trailer it took me all of about 5 minutes to get VERY frustrated with tow ratings. Problem is that EVERYBODY is motivated to over-rate how much you can pull.
The car manufacturers want you to think their truck/van/SUV is a massive powerhouse capable of anything and everything. Their ratings you expect to assume you're using every piece of assistance hardware (trailer brakes
, sway bars, WD hitches etc etc) and have stripped the vehicle of everything except the basics and a driver.
The trailer manufactures (and dealers) want to sell you the biggest damned thing they can (larger profits of course). So they'll look at whatever you've got for a tow vehicle and declare it can tow some massive behemouth. A dealer claimed we could tow "at least" 5000 lbs with our Dodge 1500 Van. Course the max tounge weight was 350lbs (if you have 10% of the trailer weight on the tounge, that ALONE limites you to 3500).
I've seen suggestions that you should basically never exceed something like 70-80% of your listed tow rating. When we were shopping, we decided to go that one better (I'm very pessimistic) and decided that 50% of the tow rating would be our max trailer weight.
Course, when it came down to it - we ended up with the lightest trailer in creation. The motivation however ended up being based less on what the VAN was capable of, but on what I was capable of. Meaning: I wanted something I could manhandle around at home or at a campsite if I wanted to. I REALLY like being able to easily manouver the Boler
by hand. It's proven a very nice feature on several occasions.
In addition: Given the ratings of the van... According to the numbers, we could load the van up with passengers, then park the Boler
on our roof and still be under our GVWR. :)