@Danny with all due respect, the manual is a very general outlook and does not really consider the temperature and conditions variances throughout the world. For me I keep my stock rim size and increase the size of my tire as I need more rubber when I am off-roading. Although my Jeep Commander Hemi stated that I should keep my tire pressure at 32 PSI with the Michelin Latitudes my tires were looking deflated even on 35 PSI, all it needed was 1 PSI more, that is, 36 PSI and it was just right.Sometimes you don't need a manual or a piece of chalk to tell you what is right, you just feel it from looking at it and driving it around.
Just my 2 fils.
BTW, I don't know many people in the UAE who follow manuals, and Carnity is a perfect community to share such information and store it long term for anybody it can help.
You can also “calculate” your tire pressure with the chalk method. This involves coloring a section of your tire with chalk to see how much tread is making contact with the ground. Start by finding a flat road surface. Concrete is actually the best choice, but you can also do this on asphalt. Make a mark with soft chalk that goes all the way across your tread. Then, gradually drive your truck forward about 50 feet and then backwards 50 feet.
Analyze the chalk on the tire. If the chalk is only worn off on the center of the tire, reduce the tire pressure slightly and go through the process again. With the adjustment, you should see the chalk wear off more broadly. Keep making tiny adjustments in the tire pressure until the chalk wears off evenly and all the way across the tread.
You will have to complete this process for each of your four tires. Once you’ve found the right street pressure, add 10% to all four tires. Then, measure the tires and add pressure to balance them. As explained above, you need to measure from the wheel to the ground. Start by balancing the profiles of the front tires with each other. Then, balance the front tires again with the rear tires. Always adjust the tires with the smaller profiles by adding air.
If you go through the process correctly, you end up with the ideal tire pressure. But, this method is tedious and there’s a reasonable chance that you will make a mistake.