Everyone has their own comfort level, but you don't really have any sidewall bulge/flex while stationary which seems to be too high of a pressure. I think the effect of watching the tire closely in the video exacerbates what you're thinking because it's pretty rare to have your eyes on the tires 100% of the time. I'm sure if I saw what my tires were doing sometimes I'd think they were about to blow. I usually run 20 psi off road, and you can definitely see the tires folding over obstacles and while it looks like it would damage them I have yet to (knock on wood). It is important to note though that I have a 16" rim so lots more sidewall, and I run E rated DTs which are probably more plies than what you run. If you bring air with you and a spare, maybe experiment with 26-28 psi to see how it works. I can definitely tell you the ride is far less bumpy over washboard and rocks with lower psi too!
I follow you 100%. I don't have any sidewall flex sitting balanced on all four corners. If I did, I wouldn't be able to keep the rim off the rocks.
I think there are two key considerations here when comparing tire pressures:
1. The amount of sidewall in similar sized tires on 16 inch wheels vs. 18 inch wheels (looks like you've got 285/75/16's?). Believe me, when I swapped my 315/75/16 clad 80 for the 275/70/18 rubber on my LX and aired down for the first time--it was depressing. You've got a lot more to work with.
2. The flex of sidewalls between different tires. Some tires are stiffer than others. Going back to my 80, I ran 295/75/16 Terra Grapplers for a number of years, and they responded in the same way as these Toyo ATIIs--they had very flexy sidewalls. I had to run them around 25 psi to keep the rims off the rock when really weighted. When I switched to 315/75/16 MTR Kevlars, I had to drop to 18 PSI to get the tires to flex. Same truck. Same weight. Stiffer tire. The MTR's stood up straight with far lower air pressure compared to the Terra Grapplers and the ATII's. By the same token the ride was harsher at the same pressure with the MTR's compared to the Terra Grapplers.
Trust me. The ATII's deform plenty over bumps, and cushion the ride admirably at 30 psi. Just because they're standing up straight when balanced evenly at all 4 corners, doesn't mean they don't easily deform around bumps. They're a soft tire.
30 PSI:
