I haven't delt with Nitto tires, but Toyos are not known for being a round tire and IMO they are highly over rated.... Highly!
Any time you go with a large tire, like a 37, getting a round one is not the "normal". Being that you are looking at a narrow tire, it will help, but still a big tire.
I'm not game with going with a D rating over E. IMO you are looking at wearing tires out faster than their rating and the warranty will be void because they are not rated for your truck.
If you are looking for for better ride quality, then spend some money on good shocks and suspension parts. If your looking for drivability, then loose the lift.
Everything we do to modify suspension has give and take. Lifts might look cool, but (hah) cause a lot of other problems. The proper way to have a lift and big *** tires costs a lot of money.

 

@6riders
Drivability and ride quality go hand in hand and subjective to individual user. What works for you may not work for me. In my opinion, OEM ride quality and drivability is poor. You make a good point w/ suspension upgrades--of which I have completed and invested money in. (Carli 2.5 Backcountry, full Deaver packs)

Do you have a preferred suspension setup that you recommend? Same w/ tire/wheel combo?

Previous to the Falken's, I ran Toyo RT's, in a 37x12.50x20. They balanced better (little to no weight) and rode better than the Falken's. My reason for change is to an 18" wheel (OEM) is to achieve additional sidewall height (1") to improve ride quality and reduce the dreaded unloaded "bounce" and harshness that's experienced on these trucks.

My thinking on the 11.5 tires: smaller width for ride quality, ability to balance, and Nitto Ridge Grapplers appear to be well reviewed. I could be wrong and need to reconsider jumping down to a 35" flavor in the 18" wheel.

 

@BMLS
I don't care for lifts on modern trucks. That's just me, you do you. My point is, if you lift, you need to buy more stuff than just the kit. You need all sorts of steering mods, upgraded steering box and etc, it gets expensive to have (even stock poor) quality ride. So no, I don't have a preference on lifts/suspension mods, besides upgraded parts.
Like I was saying about tire size; yes narrow helps with drivability and balancing, of course the overall weight of the tire, the wheel and the quality of these 2 makes a difference.
If you want to take the "harshness" out of the suspension when going over bumps (trust me I get it, I'm to old to like that ****) you have to modify all 3 components that affect this. Shocks, springs and tires. Changing just one, limits, or hides, the positive and negative results.
The tires are easily modified, take air out/add air, you might be surprised at the difference this makes.
Shocks are the 2nd place to look. The rebound of a shock creates a harsh feeling. In cars/trucks a "softer" shock has slower rebound, thus not keeping the truck so "solid" on bumps. The compression is was makes a shock (or suspension) feel "squishy". If either of these are out of balance, you get all sorts of weird feelings with the suspension. So.... The compression needs to be set so that the truck doesn't feel like it's falling to the ground when being "loaded", BUT, the rebound needs to be slow enough to keep the truck from "launching" back up to full height.
If the springs are to stiff (well duh, look at the payload) and the shocks are out of balance, you get "hit" by the suspension. Now, you can negate some of this with your tires by softening the sidewall. This can be done with air pressure (proper way) or reducing load capacity (wrong way, as noted in my prior post).
Tires being round is a huge ride quality AND drivability issue, no, they are not the same thing. Ride quality is what you feel in your back/***, drivability it what you feel in your shoulders and steering wheel. You know, leaning your body into a corner, turning the wheel with little or no response, or to much response. Drivability can be affected by the rear of the truck wanting to bounce around when turning, but, there you have a different issue.
So, to get rid of the harsh ride, you can do 2 things; get better (or adjustable shocks) or reduce spring rate, or both.
Once this is done, you can refine the ride with air pressure in the tires.
To increase drivability, you can do a lot of things, but properly adjusted shocks and steering geometry (yknow that class you never needed in high school?), and spring rate. Then tire size, wheel offset, air pressure bearings, u joints, ball joints etc.
See, it all works as one system and changing your tires and wheels WILL NOT get the results you are looking for.
Just get some RS9000s and mess with the adjusters for a couple weeks. If that doesn't help, time to remove leafs or have new springs made. If that doesn't fix it for you, buy a 1/2 ton.

 

@6riders
Keep in mind--I'm running a Carli 2.5 Backcountry kit w/ full Deaver packs out back. Tire pressure is inline w/ Carli specs; 45psi up front and 35psi out back. This seems to be the sweet spot.

Thanks for the notes--I'm going to push fwd with the 11.5's on OEM 18"s and see what happens.

 

@BMLS
A narrower tire will yeid a VERY SLIGHT increase in fuel economy on these truck especially. Talking less than .2 to .5 on modern diesels but also the whole D vs E is nothing to worry about. There are actually D rates tires with a higher rated load capacity then E rated. Not super uncommon either.

Point being. My 285/75r16 bfg ko2 at tires
Brought in 2017 are E rated to 3750lb at 80 psi yet the d rated tires you’re looking at are 3800lb plus at less PSI lol.

As long as you are getting a name brand tire generally you’re going to be just fine in quality. Never had issues with Toyos except their price

 

@JustinOOO9
Agreed on whole load range D vs. E thing. Kind of a mess that tire manufactures have created with load ratings. Mirroring what you stated with you E's being less weight than the D's I'm looking at. Plus the introduction of F ratings, things get confusing.

I'm trying to find a proper balance w/ tire size, suspension setup, and ride quality. The 37's fit well under these trucks and I'm confident in Carli's suspension. My next step is to swap over to an 18" wheel from 20". See what changes in ride quality, if no increase, then send the shocks off to Accutune for a revalve.

Thanks for your input!

 

You will notice a difference going from 20s to 18s you will feel a better ride and handle towing/corners better.

Personally 38s with an 11.5in May take some time to get use to as my whittle 285/75r16s are just about 11.5in wide but I honestly like the taller narrower tire look. Better traction in wet/snow/ice.

I may go with a 255/85r16 next tire go around it’s like a 33x10r16 cs my 32x11.5r16s (in metric of course etc).

 

Picking up a set of 2020 OEM 18" wheels today. Going to drop them off @ local powder coat for a dusting of satin black to mirror the Tremor wheels.

The infamous Toyo vs. Nitto debate came up w/ my tire guy yesterday. They are exclusive to Toyo but sell majority of other brands, Nitto being one. The topic of conversation was balance, tire roundness, etc. His comments were Nitto Ridge Grapplers, in their experience were more often than not, out of round when compared to Toyo RT's. Their suggestions were Yokohama or Toyo for true roundness. Additionally, they gave me an outstanding price on Toyo RT's in 37x12.50x18 with the 45 day or 500 mile like/dislike option.

I've run these tires in the past, 37x12.50 r20 and didn't have much to complain about. I'd say their handling is less precise than a true AT?

 

So did you get the Nitto’s? I’m currently running 315/75/r18 (36x13x18) Toyo MT’s on my 2019 F250. When these are gone I was thinking about 37x11.50 ridge grapplers or the 37x12.50 Toyo RT. I’ve also considered 37x12.50 Kanati Trail Hogs as they are 72lbs E rated tires and have good reviews. Curious to see pics on whichever way you went.