2018 F150 3.5L Ecoboost SuperCrew 157" Max Tow with the factory 18" wheels. Door sticker is 1857# payload at 35 psi. Travel trailer being towed is 5500# and 800# tongue weight via Cat scale. All #'s work out within spec when fully loaded and ready to go.

I just towed 800 miles last weekend with the truck tires at 35 psi. Throughout the trip, the highest buildup I noticed was to 39 psi in the rears and 38 in the fronts while towing in 80 degree weather. No issues on the trip.

About to leave on a 2000+ mile round trip towing down south to Florida and back. Your opinion, stay at the 35 psi or inflate to the 44psi sidewall max cold on the factory Michelin Primacy XC 275/65/18's and why? I have always followed door sticker inflation data on my other trucks, but I've stumbled across a couple of articles suggesting running the max 44 psi on these P-Metric tires.

Thanks in advance.

 

I wouldn't run the max pressure but I would run 40psi.
With only 800# tongue weight you're really not adding enough to the truck to worry about it.

 

I concur. When the tires heat up, the pressure will increase 3 or 4 PSI. So inflating them to 40 PSI will give you a stiffer sidewalls, but should also reduce the heat build up. So you may end up with around 43 PSI once they're hot. If you start with 44 PSI, the warm up will go over the max.

 

Thanks. I'll air them up to ~40 tonight when i hook up.

 

 

Guess if your tires max pressure is above 44psi that's ok to do. Sure will make it ride rougher though.

 

I would trust Ford's suggestion for the OEM-supplied tires.

 

That, and also what's printed on the tire sidewall. If the tire says 44 PSI maximum, I would try to stay inside that boundary.

 

Made it on the 1st leg of our trip. Started out at 40 cold. It hung right at 44 in all 4 tires almost all day long. Saw a couple of times to 45 on the dash display but that wasn't the norm.

Seem to be a little more stable than it was at 35psi. Going to leave them set right here for now.

 

 

I bet that's a harsh ride. Not to mention you wear out the center tread faster than the outer edges. I run my LT Falken's @ 44psi cold