Ford Powerstroke Diesel Forum banner

Different size tire pressure?

349 Views 9 Replies 7 Participants Last post by  jokester00
Swapped out the OE tires to LT285/70/17. The OE tire pressure placard states the front original LT245 at 75psi and the rear at 60psi. Is this what you guys are using with casual towing?
1 - 10 of 10 Posts
The only way to do it right, is to determine the axleloads in your use acurate and look them back in a pressure/ loadcapacity list for the needed cold pressure.
If you then also give the maximum speed you use, and wont go over for even a minute, I can make a custum made pressure/axleloadcapacity-list for you, with build in maximum reserve, at wich comfort and gripp is still acceptable, so you dont need to do precalculations yourselfes.

Need from tires next.
1. Maximum load or loadindex
2. Loadrange of your LT to determine the maxloadpressure, but if you see AT xx psi, that is what I need.
3, speedcode, less important.

Then if for normal use, and you incidentially have to transport wood or stones from 3 blocks away, you dont need to highen up, if you use lower speed. For instance , my list gives 90% used of loadcapacity calculated for the pressure for 99mph Then if those stones transported, the tires still won't overheat. When using max 50mph.
My 15 is different than yours mine reads 60 front and 80 rear.
I have same size tires on my 2006, been running 65 psi all tires, my tires are E rated.
I guess I’m a bit crazy in that I take temp readings in 3 spots along with wear measurements. Not all the time just till I find what works for the tire I’m running. Truck pretty much only pulls the 5th wheel or gooseneck horse trailer both with lots of bed weight. 65psi front gives me good even wear and heat, 65-70psi rear does the same. These are cold ratings because a lot changed when towing. 5th wheel tires are usually 65psi cold been doing this for 15 years and never lost a camper tire. I see people put 80psi in camper tires and wander why they explode, probably 90psi on a good hot day. Anyways I tend to feel the tread of my tires when I get gas and you can easily tell if you have too much or too little air in tires.
I was talking about trailer tires at 80psi not US regulated E rated truck tires. China bombs at 80psi in heat I don’t think is a good idea. 80psi in a E rated tire with a heavy 5th wheel for me would wear the center down at an alarming rate.
10ply (E) Cooper Discoverer STT Pros here

I run mine at 55psi normal every day driving and 75psi when i'm towing (all pressures are cold)

1 - 10 of 10 Posts