'P' to 'E' tire swap

[Jopopsy]

And straight from Ford’s mouth.

https://www.f150forum.com/f118/lt-ti...2/#post5660233

[curver900]

Originally Posted by repacs0103

Ah makes perfect sense.

As for the charts I agree that’s ideal- but the statement that running at max psi will cause premature wear in the center of the tread is just not true, at least in my experience. I run my F350 tires at 80 year round in the back; my steers run 65 in the summer and 80 in the winter when it carries a plow, and I’ve never had any abnormal wear. I also run my wife’s car at 45 with a max sidewall pressure of 48 because I want fuel mileage- 67,000 miles and counting on her Goodyear Eagle Sports and zero center wear on tires loaded nowhere near max.

Food for thought.


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curious what is calculated MPG delta is between max tire pressure and recommended?

[repacs0103]

Originally Posted by curver900

curious what is calculated MPG delta is between max tire pressure and recommended?

No idea, we don’t calculate her car. I’ve always ran near sidewall max on all our vehicles because I’ve never suffered any ill effects from it and it’s habit because I run my trucks past gvw and tow rating.

I’m one of those that ignores the door placard because I’ve never ran the same tires that the door sticker referenced as I don’t buy new vehicles.


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[ShawnR]

I like the research you're doing here. I'm in a similar situation with my 1/2 ton and E rated tires. I run 35 daily and 45 towing. My sticker is about 3900 lbs at 35 psi. I know similar aluminum rims max out at 60 so no way do I air up to 80. E is overkill but I like the rigidity and durability of the heavier tires. I have the inflation chart also but other beat me to it.

[GrumpyDad]

Now I'm no expert, but I always wondered this. With the stiffer sidewalls on a lighter truck, when running them at lower pressures, do you introduce extra heat by flexing those stiff sidewalls?

I've never run lower than 50 PSI on the E-rated tires on half tons or any truck. But that's not based on any science at all.

[Jopopsy]

I think that's where the load chart comes in. Each tire is rated for 'x' amount of pounds at 'x' amount of pressure. Yes a tire generates more heat when inflated less, but if the tire is inflated less that 'should' mean its carrying less weight.

A max inflated tire carrying its max load should generate the same heat as the same tire inflated to 45psi carrying the appropriate load for 45 psi.

[Atlee]

Unless the truck comes OEM with LRE tires, which mine does.

And the tire stricker on the door says 55# psi in the front tires and 60# psi in the rear tires.

Originally Posted by 2naEagle

Glad that helps. A load range "E" is a lot of tire for a F150.

[Jopopsy]

You have the HD package on a steel truck - I bet your axle ratings are much higher then us aluminum trucks with standard axles.

[Atlee]

That is true. 4050# in the front, and 4800# in the rear. I pull a middle weight trailer, 23RB. It has a 6500# GVWR and is 27' long. But it definitely pulls nicely behind my truck.

One drawback to the HDPP is the requirement of having a long bed. Because of this, my SuperCab has the 8' bed and 163" wheel base. Great stability towing, but hell in a parking lot.

This is the combo I plan on using until I get to the point of just not feeling like doing Rv'ing any longer.

Originally Posted by Jopopsy

You have the HD package on a steel truck - I bet your axle ratings are much higher then us aluminum trucks with standard axles.

[Jopopsy]

Originally Posted by Atlee

That is true. 4050# in the front, and 4800# in the rear.

That’s a big swing from the 3450/3800 that the rest of us have. 17 inch tires (if you have them) I think would also dictate higher pressure.

That plus your HD rims would all add up to a higher psi number on your placard.

[Atlee]

This is all true. I used to have a 2005 F150 XLT, 4x4, 6.5' box, 5.4L Triton engine. I used it to pull a trailer from VA to CA and return. But the trailer was even light than what i have now. It's GVWR was only 4990.

When I decided to change trucks, I intentionally went looking for a truck with the HDPP. My old truck had a CC of 1400+. I wasn't going to trade for a new truck where I gained only a couple of hundred pounds of cargo capacity. My Virginia dealer finally found 4 HDPP equipped trucks up in Pennsylvania. He secured one and here I am. My current 2014 all steel HDPP truck has a CC of 2286#.

Originally Posted by Jopopsy

That’s a big swing from the 3450/3800 that the rest of us have. 17 inch tires (if you have them) I think would also dictate higher pressure.

That plus your HD rims would all add up to a higher psi number on your placard.