A data point. I have E General Grabber AT/X and at 40PSI they feel great on a gravel driveway but a little spongy on the highway.
At 45PSI they feel bouncy on a gravel driveway but great on the highway.
Might try 42PSI.
Is yours in stock size too? Mine running at 42 psi would straight up bounce the wheels off the ground on shitty LA roads. My 4r is pretty lightly loaded at the moment, too.
Also update, based on inflation table for LT265/65r17, looks like even 35 psi is way above 4runner's max GAWR (3530 vs 3050)... Non of the inflation tables that I have contains data for <35psi, I guess it's unknown territory lol. Now I have put on about 300 miles on/off road, they feel significantly better behaved at around 37. I went through the same bumpy road few times with different pressure (just in case anybody lives around me it's wilshire blvd between Western and Berendo east bound), and 39 is the threshold for wheels to remain planted. I assume that will change when I someday load it up.
The other fun fact I've found is, yes load rating is the bottom line that anybody running LT should not pass under any circumstances on road. But manufacturers do not design their recommended cold pressure based on it
alone. For HD trucks, the recommended pressure is much closer to the load rating required for GAWR; GX460, has its recommended cold pressure right at the load rating (
only 10 pounds above). 4runner's 32 psi on 265/65r17 also puts tires way above its actual GVWR, so that must be because of other factors. I can think of corner grip, ride quality, dampening or even rollover resistance. For some reason, manufacturers prefer oversteer or understeer compared to rolling over (I would too), and more stiffness from the tire is definitely a measure. I will say as much as that original thread (LT tires require higher pressure) is very thoroughly explained, it left some unexplained things in its argument, eg. 5th gen limited load rating, GX460 load rating and etc. Also DOT completely ignored medium and large SUV sometimes put on OEM LT tires to boost offroad durability and capability, and proceeds to mandate the 46 psi requirement. Imagine running 46 psi on 285 on an FJ.
Don't know about you all, I'm gonna go with 35 psi as the hard deck, since anything below is undefined and I don't know if the correlation between load and pressure is linear in that region.
