Originally Posted by jaakkandy
I have a 2010 V10 F250 with 4.10 gears. I would like to know if I am able to tow a 12750lb 5th wheel comfortably.
GCWR = 21,000 pounds
Tow rating for a 4x4 = 14,100 only when the wet and loaded truck weighs 6,900 pounds or less.
But your wet and loaded F-250 will probably weigh closer to 8,250 pounds.
21,000 minus 8,250 = 12,750, which just happens to be the maximum actual tow rating you need.
So probably you'll barely have enough power and torque to climb an interstate mountain pass. No, I would not be "comfortable" when climbing that pass. But that truck if well-maintained can getter done, as far as power and torque are concerned.
If your truck grosses 8,250 when wet and loaded for the road, including all the people and stuff and 5er hitch and a full tank of gas, that leaves you only 1,750 pounds for max kingpin weight before you exceed the GVWR of your F-250. A 12,500 5er is probably going to have minimum pin weight of around 2,250 (18% of gross trailer weight), so you're probably going to be overloaded by at least 500 pounds, and maybe more.
If you haven't heard it before, you're hearing it now: you'll exceed the payload capacity of your F-250 long before you reach the tow rating.
Available payload capacity for pin weight = 10,000 GVWR minus the weight of the wet and loaded truck.
Max gross weight of the trailer (actual tow rating) your available pulling power can handle without burning up the drivetrain or being the slowpoke holding up traffic on hills and mountain passes = 21,000 GCWR minus the weight of the wet and loaded truck.
Conclusion: That F-250 is not enough truck for that trailer. You may barely have enough power and torque, but you'll probably overload the F-250's suspension with the hitch weight of that trailer.
Next step: Load the truck with everything and everybody that will be in it when towing, including the 5er hitch, and any pets, toys, campfire wood and tools you'll probably haul when towing. Go to a truckstop that has a CAT scale, fill up with gas, and weigh the wet and loaded pickup. If it weighs more than 7,750, then that trailer will overload your F-250 with hitch weight of 18%. (Average pin weight of a 12,750 pound 5er is 18 to 20 percent of gross trailer weight.)
Recommendation: Back off on the weight of the trailer to have wet and loaded trailer weight of around 10,000 pounds or less. They're out there.