Tire Load Inflation Table (longer read)

has anyone used this to figure out what psi to run in their tires? i uploaded the pdf i was using.

stock, the tires are P245 75 16 and the factory psi recommended in the door tag is 29 psi. i upgraded to p265 70 16s which are marginally larger.

first i did the chalk test, and according to my results i needed to run about 31 psi in them. so i did that first and i noticed they were wearing down the middle faster than the rest of the tire. so i lowered it to 29psi like the factory tires. they still were wearing down faster in the center of the tire. so i read this document, and i'm now getting that i should be running around 26 psi in the tires. i just lowered the psi yesterday, so i cannot confirm that the tires are wearing more evenly or not.

after i lowered the psi is when i read in this document how if you are running a P-metric tire on a light truck, you need to reduce the load capacity of the tire by a 1.1 factor. this is the part i am a little confused about, becuase if you take that into account that puts me back up at the 29 psi mark again which is where the tires seemed over inflated from the way the tire was wearing.

am i looking at this thing correctly???

 

I quickly looked through what you posted and my head hurts... I'm sure there is a mathmatical way to determine optimal tire pressure given sidewall stiffness, tread pattern, vehicle weight, etc but I just stick to the chaulk test and visual inspection. If they start wearing unevenly, I just make adjustments to the pressure. FWIW, I'm running 265/70R17 Cooper AT3 at 35 PSI front and back. Wear seems to be even.