I know tire pressure with aftermarket wheel/tire set up is very subjective.
I have a 2015 Supercrew with the 5.0, 2-WD and a set of Nitto Terra Grapplers G2's - LT 275/70 18.
Sidewall has a PSI rating of up to 80lbs. Wont be towing/hauling anything very heavy.
Anybody have a preferred pressure they run on similar tire size?

 

I still used psi on Door sticker even though I've changed tire size/type.

 

I have E rated 275/70/18's on my truck. You'll just have to experiment. You'll get the best ride with the numbers on the door but fuel mileage will suffer and you'll not be able to carry much weight at that level. The 80 PSI is for heavy duty trucks, your wheels and valve stems aren't rated to hold together with that much air in the tires. I found 45-50 PSI was a good balance of good fuel mileage and ride. The old factory tires were rated to have 44 PSI for hauling and I always kept 38-40 PSI in them anyway. Fuel mileage is a little better and when I needed to haul something I didn't have to stop and air them up before loading the truck and then air them down after.

 

I'm running 295/70-17E and the biggest thing I tow is about 5000 lb with approx. 350-400 on the tongue. I run my tires at 42 and its plenty. The sidewalls don't display any more apparent squat than when unloaded and they don't squirm when cornering.

 

You could use the chalk test.

https://www.intercotire.com/using_ch...etermining_psi

 

I go by MAX TIRE PSI on tire itself if using a different tire than on door sticker . But i usually go a few lbs under MAX PSI .

 

For the best results, follow your door placard. The TPMS is calibrated to that pressure regardless of any tire/wheel you install on the truck.

Failure to do so can cause a system error resulting in an amber warning light on your dash.
.

 

Thanks. Trial and error was my plan of attack. Start in the middle and try a little more or less.
I'm not sure the truck is even rated for the kind of weight the tire is rated for at 80 lbs.

 

Only if you're reducing psi. I would assume most are planning on increasing.

 

Not even close. The tires are probably about 3600 lb each.