I have a 2018 Ford F150 XLT 3.5L Ecoboost Supercrew 145", 4x2, 3.55 Axle Ratio, 10-Speed Automatic with Tow Mode. I have the Max Trailer Tow Package. My hitch is a Class IV with ratings of 13200 / 1320 with Weight Distribution and 5000 / 500 Carrying Weight. My GVWR is 6750. Payload 1845. Tires are 245/70R17 T110 (Max Load 2337). I will be using a weight distributing hitch. Added weight in the truck would be about 600lb for driver, passengers and extras. How much can I safely tow with this vehicle? What are the calculations I need to make to determine the safe weight of towing a travel trailer

 

1,845 - 600 = 1,245. Minus 100 for a wdh = 1,145. 1,145 / .13 = 8,807 pounds for a LOADED trailer.

Many put 1,000 - 1,500 pounds of stuff in their travel trailer including batteries, propane, water, food, pots and pans, ...

 

Generally, figure about 8,000 max wet and loaded trailer weight, leaving almost no wiggle room without overloading the F-150. And that's assuming you haul absolutely nothing in the bed. A better estimate would probably be a TT with GVWR of less than 7,000 pounds.

And if you want a really good estimate, then load the F-150 with everybody and everything that might be in it when towing. Tools and jacks and jack stands, patio rug and outdoor furniture, campfire wood and fire starter, cast iron Dutch oven, toys such as bicycles and trycycles and scooters. Generator and fuel for the generator? Everything that weighs more than a handkerchief that you might haul in the cab or bed of the tow vehicle. Then fill up with gas and weigh the wet and loaded F-150. Subtract the weight of the wet and loaded F-150 from the GVWR of the F-150. The answer is the payload capacity available for hitch weight. Subtract another 100 pounds for a good WD hitch, and the answer is the payload capacity available for tongue weight (TW). Divide the payload capacity available for TW by 13% and the answer is the max GVWR of any TT or cargo or tandem-axle utility trailer you want to consider towing with that F-150 when loaded with your family an camping stuff.

And pay attention to that little word "max." It does NOT mean "about" or "in the ball park", it means the absolute maximum.

 

I think you're under estimating the weight of passengers and extras in the truck. Put it on some scales and subtract that number from your GVWR. That will be your true Payload number. But around 7000-8000 lbs is a realistic number. If you're really not putting any more than 600 lbs in the truck maybe closer to 9000.