Looking at the 2014 Towing Guide, I'm curious why two similar Supercrew trucks with 157" wheelbase and 3.55 rear axle have 2,000 pounds difference in GCWR and 2,000 pounds maximum loaded trailer weight. The only difference between the two is one is a 5.0 Coyote and the other the 3.5 Ecoboost. I'm assuming the suspension, frame, wheels, transmission and trailer tow package are the same in both trucks. The 5.0 comes in at 7,500 pounds and the 3.5 at 9,500 pounds. I'm having a hard time believing there is that much weight difference in just the two engines. Credible suggestions are welcome, as are sophisticated wild *** guesses, but please don't turn this into another "my engine is better than yours" tirade. Thanks

 

The number you are looking for is payload.

GROSS VEHICLE WEIGHT RATING (GVWR) is the total weight of the truck, cargo, and passengers.

Gross COMBINED Weight Rating (GCWR) is all of the above plus trailer weight.

TOWING CAPACITY is the weight of the trailer you can pull.

PAYLOAD is how much weight you can add to the truck not including a trailer.

The 3.5 is the more powerful engine with a TOWING CAPACITY of 9500 lbs and a GCWR of 15,500.

The less powerful 5.0 has a TOWING CAPACITY 7500 lbs and a GCWR of 13,500.

Because the 5.0 is the lighter engine it will have more PAYLOAD, but because the engine is less powerful is rated for 2000 lbs less in both trailer weight rating and total weight rating.

Anything you do to make the truck lighter, including the engine, will improve payload. But it won't help you pull a heavier trailer.

On paper the 3.5 will tow 2000 lbs more weight; but both the 3.5 and 5.0 will likely max out on GVWR before you max out on towing capacity. Since the 5.0 will have more payload the real world difference in towing is a little less than 2000 lbs.

 

Thanks for explaining it in simple terms, I have just enough mechanical knowledge to be dangerous, so it makes a little more sense. We have a 4 horse trailer, and by the time it's loaded and four of us in the truck, we scaled at just under 13,000. The 3.5 is rated higher horsepower, so that's where the greater towing capacity comes from. It has nothing to do with the physical capability of the suspension. So if I can make an assumption - the 3.5 develops more horsepower due to twin turbos forcing air into the combustion chambers, then if a 5.0 had increased air flow also, it would develop more than rated horsepower and pull a 7,500 pound trailer easier than a stock 5.0?

 

In my opinion it's mostly marketing to sell the Ecoboost.

People get wrapped around the axle about this crap in the half ton world.

Frame, suspension, axle/tire ratings, and brakes are the safety factors in towing, not the engine hp/torque.

That said, 13k is a bit much for a half ton, IMHO. You're really into the 3/4 ton realm with that trailer weight.

My background is years of towing commercially and personally. Mostly diesel trucks in 3/4 and 1 ton variants plus about 6 years in the tractor/trailer world.

 

Here is some more food for thought.

As an example, Tow ratings for supercrew short boxes:
2011 5.0 3.55: 7700
2011 5.0 3.73: 9300

Do you really think this has anything to do with safety? In this case it is purely what Ford is willing to do warranty work on for a towing F150. With 3.73s you're putting less strain on the driveline than with 3.55s.

Again, nothing to do with safety.

In an F150 with a 9.75 axle your safe towing limit is limited by your rear axles relatively low weight rating of 4500# (compared to larger 3/4 ton and 1 tons) and the lighter duty suspension (which can be easily solved with airbags)