I went to NTB a few days back to replace my P Rated Cooper RTX (265/75R16) - it's their version of the AT2. Turns out they installed the LT version of the tire by mistake (among other screw ups that I won't get into). They were closing but the guy offered to swap them for the P rated if I came back. So I'm trying to figure out if I should.

I really don't offroad all that much and I never tow. I definitely don't *need* LT tires. That said, they do look kinda cool, and the improved durability is a plus. I thought the increased tire weight (50 lbs vs 40 lbs) would have a big effect on efficiency but I'm not seeing all that much. It's a bit hard to say, because I haven't had enough time to do a full tank's worth of driving to compare, but the Ultra-gauge is showing about ~15 mpg in the city. What surprised me is that the highway mpg was actually higher than my usual - 23.5 vs about 21.5 on P rated RTX. Maybe from the higher PSI and stiffness? The 4Runner is basically stock, FWIW.

Also surprising, I'm not really detecting a rougher ride that everyone talks about. I'm running the OME 906 so it's kinda rough already.

I'm wondering if all the stuff online about bad mileage and stiff ride is because most people go from a P-rated highway tire to a E-rated AT tire. Who would go from P to E with the exact same model and size (except me)?

Should I go back to the P, since the E is definitely overkill? Or keep the E since I got them at good price and I'm not seeing any negatives with the ride or much of a dent with mpg, at least on the highway? Assuming that the LT reduce efficiency by 1 mph, that's about $500 over the life of the tire, so it's not nothing.

If, during an emergency, you want to drive over a curb or highway median or some other lumpy ground, it's better on LT than P-series (the "P" stands for Paper thin, btw).

3 ply sidewall of E rated tire has a lot less roll, 7 ply's under tread better with puncture resistance.

I'm pretty sure you've answered your own question here. Although my experience has been quite opposite with much harsher ride and worse MPGs with E tires. Also, I've been wheeling with guys running P rated tires while aired down on very rough trails and did surprisingly well. But if your not seeing any negatives, I'd say stick with the E.

I kinda realized that as I was writing it out... I was hoping someone would come in here with some mpg data that might make the decision easier. I always get wary when my personal experience doesn't with the expert consensus. Like, I'm probably underestimating how bad the city mileage is, right?

Then again, everyone also told me the OME 906's would ride rough unloaded, didn't bother me in the least.

Other than pastures, logging roads, and farm fields I don't do any offroading. I got a deal on some LT's a few years back. I got em and hated the days till I got back into a P tire. The ride was terrible.

That's right. Aired up to the proper psi you should see an improvement in cornering. Also if you're like me you've never owned a tire that didn't pick up a screw or something. Plug repairs work everytime with stronger tires.

It's all relative to the nut that connects seat to steering wheel, gotta make some data.
I'm after ROI tread life, tire psi for my gvw figured out using chalk test the ride/mpg's are what they are.
Doesn't work for you go back to P or adjust things for ride and mpg's not the air pressure.
I adjusted things, current mpg/ride data stock weight 3" lift 85# E rated 33's 12-15 varies with traffic hwy best 19.5
It rides as well as stock I think so does alignment tech he mentioned after test drive passengers don't count.
1 gear change, on 3rd suspension with tweaks to 3rd all it took for this nut seat steering wheel combo to work.