When towing, I take the rears up 5 psi to 65. I tried increased pressures on the fronts, but tow steering is still most stable at the spec 55 psi.

Rob

I was thinking 65 on the rear as well, thanks.

have an F250 with Goodyear Wrangler tires (form factory). Max pressure is 80 psi on those....however Ford suggests 60 PSI for front and 65 psi for rear. When towing I typically go 70 PSI front and 75 PSI rear.

Basically the 80 PSI is for the maximum load rating of the tire. When you have less load on the tire than the maximum load rating, the PSI requirements are less.

In my opinion you do what works best for your setup. The suggestion to take tire temp and inflate if too hot is a great suggestion.

I've upgraded the OEM GY tires on my half ton GMC where the door label specifies 35 psi. Discount tire did install the E rated tires on my truck and aired them up to the pressure listed in the door jamb. This is due to the yellow tag being the final word on the recommended pressure that GM specified. Discount tire typically will not go beyond that due to liability.
Unless there is language in the owners manual on adding pressure for towing, the pressure listed in the door jamb is the recommended pressure be it towing or non towing.
Having written that, I was interested in purchasing E rated tires for my half ton and checked with the rim engineers who mentioned they would not go above 60 psi on my factory aluminum rims. I made the change and played with pressure during towing and found that 50 psi on the rear and 45 psi on the front provided the best towing experience while maintaining a good contact patch with the ground to provide the best handling. For non-towing, I air all four E rated tires to 40 psi in an effort to maintain ride quality.
If I had to do this over, I would go with a D rated tire where I believe the same goals could have been achieved where the non-towing ride quality would have been closer to the original tires that came on the truck. There are always trade offs when making changes from the original design intent of the vehicle.
IMHO, it could be dangerous to air up an E rated tire to its max sidewall pressure if installed on a half ton rim.

I've made similar changes to the TV and installed GY Endurance E rated tires on my rims that were designed for D rated tires. As a result, goodyears inflation tables are used where I air the tires from 60-65 psi to increase durability, and to maintain ride quality of the trailer and to not stress the OEM Westlake rims. This was verified with Westlake who approved the change while staying with the pressure posted on the yellow tag on my Imagine.

Hope this helps,

Jim

My F350 with oem wrangler tires has door post pressures of 65psi front and 80psi rear.

Well, there you go. Probably has to do with payload capacity

I think y'all are over thinking this thread. It all depends on the weight the tire is carrying and it's stated inflation. A tire carrying its rated capacity should be inflated to it's stated pressure. Remember over inflated will cause the tire to wear it's center tread, under inflated will wear outside tire edges. Just saying.

Underinflated will also result in the tires running hotter due to more flexing. Said to be a leading cause of tire failure.

My 2014 f350 noted 65psi rear, but to go to 80psi when towing.

Thank you, Jim. This is very helpful. If I had it to do again, I would have put the exact same tire back on and was looking at them. The Coopers I put on were a little less money and I have been a fan for years. When I looked at the SL tire for Cooper, it didn't come in a 70 sidewall like the one I replaced. This was after the fact. Discount asked where I wanted the pressure when they were installing them. This is when I discovered the difference. I told them 60 PSI.

Having said that, I changed to a new WDH this morning and didn't want to set it up with my old tires on. The tires are set at 62 front and 65 rear. I will likely lighten that a little. My test run with the new hitch went well but it was a bit of a different ride with the new tires than what I'm used to.

Thanks to all for the comments.