ocdF150

Hey guys. Need some help. Just picked up my 2015 Lariat SuperCrew on Saturday. While going through my owner's manual, playing with settings on the dash, I noticed one of my tires was a couple pounds below the others. I went to a gas station to put some air in, and here's where I came across my problem.

The sticker on my door jamb says tire inflation pressure should be 35psi cold. At the gas station (about 4 miles away) my tires are at 44psi roughly. I know driving adds give or take 4psi when warm but this seems like way more than that. I have the Hanook Dynapro ATM 275/55R20s. I can't find the recommended tire pressure anywhere to save my life. All I can find is that the max pressure is 51, this is from the sidewall of the tire.

So my question is what should I be running my tires at to be safe and also to keep tread wear even? Is my door jamb really right? Any help you could provide would be great. Thanks!

chickenwire

All stock from the factory? Did you order special wheels/tires?

ocdF150

Came on the truck from the factory. Hanook DynaPro ATM 275/55R20. Door jamb says 35psi cold, tires are at about 41-44 cold-warm. I can't imagine they would overinflate the tires that much, so I'm thinking there's a reason or a recommendation somewhere, I just can't seem to find it.

Feathermerchant

What is the max inflation pressure marked on the sidewall?

ocdF150

51

Feathermerchant

I would not worry about the slight inflation over the sticker. For now I would air the lowest one to match the others then check again when they are cold.

jadatis

The 35 psi iof your car advice is the AT-pressure of a normal car tire called P-tire in America.
this is an advice they give more often these days , they dont calculate anymore for the load on tire as they did in earliėr days.
The 51 is the maximum allowed cold pressure wich they give on P-tires ( standard load AT press 35 psi and XL/Reinforced/Extraload 41 psi).
From C-load LT tires they give AT pressure on sidewall and you are allowed to fill higher even.

The AT pressure /reference-pressure/maxloadpressure is the pressure the tire makers calculated the maximum load for up to maximum speed of tire , or if lower 160km/99m/h. And thats always the case for SL and XL// P-tires. Cold pressure is for when inside tire is outside tire temp of 18 degr C/65degr F).
Speedrating is mosly T ( 180km/112m?/h) or higher .
And thats what the difference between ATpressure/// and maximum cold pressure is used for, to highen up the AT-pressure with a system depending on speedcode. Also a little for camber angle ( alighnment wheels like this on the imaginary axle /-\ larger then 2 degrees)

So if you search the tires for more info ( XL// or not, speedcode and Loadindex or maximum load) and of car weighed loads on seperate tires in the loading you use, second best axle weighing, third best Gross axle and vehicle weight ratings ( GAWR, GVWR) and speed you wont go over for even a minute in your use, I am able to calculate an advice pressure for you, with some reserve but not to much so comfort and gripp gets unacceptable.

Greatings from a Dutch Pigheaded self declared tirepressure-specialist

Ironstar

I would keep your tires at 35 psi cold, yes the tires say 51 max pressure but to get optimal tread wear and performance the best thing to do is go by the sticker on your door and when you drive they will fluctuate a little but i wouldn't worry about that to much, if you over inflate you'll wear the center of your tires out and under inflation causes wear on the shoulders..i've worked with a wide variety of tires sizes/brands doing my job, so imo going by the door is a safe bet every time

ocdF150

Thanks for all of your replies guys, very helpful. Since I was supposed to go to the dealer and have a nitrogen fill done tomorrow morning (they threw it in when I bought), I was freaking out about tire pressure, so I called Hankook directly. The guy on the phone knew the answer to my question right away, and said I'm not the first person to call.

He said the door sticker is the recommended pressure of stock "factory" tires, but since they put Hankooks on, they fill them to their "recommended" pressure. And the "recommended" pressure (at least from Hankook) is 90% of your max tire pressure from the sidewall, so for me that's 51psi. So do the math, 51 * .9 = ~45psi, which explains why I'm seeing around 43-44.

I can rest easy now. Thanks again for everyone's responses and suggestions!

CardiacCat