I've heard and read that one should try not to exceed 80% of the stated tow capacity of the TV. This builds in a factor of safety.
I'm looking at a Grand Design Imagine 2500RL with a UVW of 5,857 lbs and a GVWR of 7,495 lbs and a hitch weight of 581 bs.
If I assume a normal trailer weight of say 7,000 lbs. and I want that to be my 80% mark, I need to look for a max tow capacity of 8,750 lbs.
We're looking at a F-150 5.0l 4X4 with 6.5 ft bed (157" wheelbase)and 3.73 axle. Its stated towing capacity is 11,600; with a WDH the hitch capacity is 1,320 lbs., and the max payload is 2,640 (with Heavy Duty Payload Package).
So,
Trailer Weight = 7,500 lbs. < 80% of truck's towing capacity = 9,280 lbs.(0.8 x 11,600 lbs.)
Hitch weight is 581 lbs. < truck's hitch capacity (with WDH) of 1,320 lbs.
Payload: me and the wife-420 lbs., dog-65 lbs., firewood-200 lbs., hitch weight-581 lbs. = 1,266 lbs. << 2,640 lbs.
The numbers seem to work well...
Am I missing anything?