Shrdlu

Any recommendations for increasing the standard tire pressure when towing or hauling heavy?

This will be my first Ford in years, but other trucks and SUVs often specify increased psi on the payload/tire pressure placard, especially for the rears. The 35 psi I've noticed on some of the posted F 150 payload images seems low for towing, say, anything over 5,000 lbs.

BCMIF150

I always air up to 40 psi when I'm towing my trailer.

linnwgetin

My thinking on this has always been, if you need added tire pressure you have too much tongue weight. I added nitrogen to my 15' platinum tires so adding air to tow would be a little tough anyways.

Bandito

I've only owned Fords in recent years and not one of their manuals has ever recommended a change in tire pressure for towing. Changing the tire pressure for towing seems counterintuitive to me. Why make the ride harsher to tow?

packplantpath

Because your tire load ratings are dependent on psi. Heavier load call for more psi. But it varies by tire rating. To find out you really need to find the tire manufacturers load ratings. Know your axle weights and it is easy to find out what the proper psi is for the load. Otherwise it is guessing. Yes, it will be harsher but you will have less sidewall flex, especially on a p-rated tire. Less heat buildup, less chance of blowout.

Lucky Dog

For me its not a matter of "ride" its all about "stability." Going from a P rated tire with a two-ply sidewall to a load rated tire with 6, 8 or 10 ply sidewalls will also result in a harsher ride, but a much more stable ride when towing. For those that seldom tow the stock P rated tires may be fine, but I tow a lot and for me having the load rated tires with a much stiffer sidewall is the only way to go. I also boost the pressure in the rear tires when towing. I typically run 32 to 35 pounds and will boost it up to 40 or 45 when towing heavy loads long distance at high speeds or with an anticipated cross wind. IMO it just makes for a much more solid feel when dealing with a heavy load (my camp trailer weighs 6500# dry) especially in a cross wind or when passing big rigs on the freeway. Maybe doesn't work for all, but it works for me.

packplantpath

I'd check on that. With LT tires, most have you run higher pressure to have the same load capacity of the stock p rated. I keep our Lt tires over 40 all the time and boost near 50 towing. But it depends on the load rating and the tire. Your unloaded ride quality is likely better at 35, but you may be increasing wear. You really need to inflate the Lt tires to a psi that matches the load rating of the stock tires at 35 psi like on the door sticker. You might also be perfectly OK, but lots of people are unaware that most Lt tires actually require higher pressure to achieve the same load reading as a p metric. Worth looking and pointing out, even if I'm wrong

jadatis

Packplantpach is writing the right things, and even manages to write it more compact then me.
A stiffer tire needs more pressure for the same load then a less stiff tire.
So if a P-tire needs for instance 35 psi for the load, then a D load tire needs for instance mayby even 45 psi for that same load. C-load in between of that.
Its not that the comfort of a stiffer tire is less because of the stiffer material .
I had myself written that those tires material is not that much stiffer then a P-tire. More a snowball effect , the little more stifnes gives little more overgoing curve wich needs higher pressure and wich on its turn gives a larger overgoing curve. The deflection though is the same wich is leading for the comfort.
Once made a paint-picture of it to show what happens, and ofcource part of the stifness is made by the stiffer material but most is because of the higher pressure .
Its all because of the overgoing curve from unloaded tire radius to to flat on the ground. The curve of that is larger for a stiffer tire.
In the beginning of my tirepressure-story I did not think this overgoing curve was that important , but it proves to be influencing the surface on the ground imensely , and with that the load to carry .




To make this long story short, I can calculate the needed pressure if you give the tire data and car data accurate.

That is from tires the maximum load or loadindex, pressure needed for that or the kind of tire so I can determine it, and the speedcode of tire wich stands for the maximum allowed speed of tire. Tire sises would be nice.

then from car, best is seperate weighed wheel( pair) loads in the situation you drive , second best axle weighing for that, but mostly we have to do with the GAWR's and GVWR ( Gross Axle/Vehicle Weight Rating) , Empty weight and the way you load it for the situation ( so persons and load and where and weight on towbar).
Also the maximum speed you wont go over for even a minute.

By law you are not allowed to go over the GAWR's so maximum load on the axles are not allowed to be more then that, not even when towing, and american cars mostly have a GAWR rear with enaugh reserve for the 10% to 15% of trailers GVWR, on the towbar .

Practice though can prove different and rear can be overloaded a little together with some unequal weight R/L , wich needs pressure for the wheel on the axle with highest load , wich can be more then half the GAWR then.

So if we use the GAWR's , to calculate the needed pressure , we are pretty save , even when towing.
The use of a Weight distribution Hich lowers the weight on rear tires of car and transports that part to front tires and tires of trailer. This needs lower pressure for rear.


Many American cars have aftermarked tires with higher Loadrange, original is most P-tire to C-load, for wich Pressure advice is given for maximum loaded , so GAWR's are filled in the American formula, wich leads to lower pressure then the European formula , wich America stepped over to as late as 2005 ( after the Ford/Firestone-Affaire) , but only for P-tires and XL/reinforced/Extraload .

Greatings from a Dutch Pigheaded self declared tire-pressure specialist.

brulaz

Don't think you're wrong.

The idiots who put on my LT-E tires insisted that the 35psi of the original P rated tires was correct. When I contacted Michelin they said no, 48 psi would match the load carrying capacity of the P tires. But I'm running 60psi now.

With the original P tires, I filled them to the max allowable that was listed on their sidewall. Think it was 44psi? and helped some with the squirm. I understand that there are some heavy duty P rated tires out there now that allow you to go to even higher pressures. But since I'm fully loaded most of the time, decided to upgrade to LT-E's.