I know everyone is gonna say search thread to find my answer but I like many are lazy and just want a answer/a idea what everyone is running. More specifically what you are running for 35x12.5. Ive done some research online and people say how they weigh the front of the truck then the rear or the truck to weight how much weight is on each wheel. Thing is I don't have a scale for my truck lol, I have a 2016 F250 XL Regular Cab (roughly 5800 pounds?), 35x12.5 R17s, E Rated, Cooper Discover MTPs. Now I have a 3.5in rough country lift (with the original shocks that I recently swapped out for fox shocks) Im still not entirely impressed about the ride. And yes I understand its a 3/4 heavy duty truck, its not gonna ride like a Cadillac but im wondering if my tire pressure its just to high, bc its not enjoyable at all when im off-roading.I mean Im not looking to constantly be airing up and down everytime I off-road but i just wanna find some middle ground I guess? Originally it was set at 65 PSI, which a while ago I set to 50 front, 45 Rear for PSI. I dont wanna keep airing down if its gonna be unsafe to drive? Ive heard people airing down the 35s to 40 front 35 rear but they were with D rating tires. Can anyone sent me some info bout this? Would be much appreciated!

 

Many tire manufacturers publish load inflation tables which can be used to determine the specific tire inflation for various weights. here's the one for TOYO: https://www.toyotires.com/media/3729...s_20200723.pdf

 

Running empty, I run between 35 and 40. Loaded I run more according to the weight.

 

What load tire do you have E? And you have a f250 i assume? I’m currently at 60F, 57R and still feels a little tough. I’m thinking about doing the “chalk test” aswell.
(I miss spoke about my tire pressure in my original post)

 

Truck specs are in my Sig line.
Cooper Discover AT3 E rated tires in 295/75R17.

I just did a 3000 mile road trip in her with no issues and tires wore fine. Ride is a little softer than when I got it and the tires were up around 60 PSI. I also have changed the shocks out to Blistine 5100's. I ran them at 55 PSI when I pulled a bumper pull toy hauler.
I forgot to air them up one day when I loaded about 2500 lbs of concrete bags in the bed. But she took it all in stride. Truck has the factory overload springs so it's basically a f350.

I set my pressures off of the truck weight and the tire manufactures list of how much air per weight as in the list posted above. Empty with the tires I have and the weight of the truck, Cooper says around 35 PSI. I also look at the tire patch on the road and the wear pattern to make sure they are wearing evenly across the tread. That's the best way to tell.
Over inflate will wear out the center. Under inflate will wear out the outer edges.

 

The tire chart that Erngyver linked is very helpful. I recently switched from 275/70r18 to 295/60r20 tires. The chart had me adjust the tires from 65psi to 62 psi to still be in compliance with the load rating of 3195lbs per tire.

That being said, this issue may not be tire inflation but other components that have been combined to make for a rougher ride.
Tires: Different tires alone can make a huge difference in ride quality. Some are built with comfort in mind whereas others are built with durability. While they may have the same "E" rated load capacity, their design and structure can differ making one tire ride much better than another.
Shocks: The Fox shocks are awesome and built for offroad; however, their drawback is that they are built for offroad and ride more firm. I'm debating new shocks (current stock Ranchos have 51k on them) and am leaning towards the Bilstein 5100s. From a few reviews I read online and talking to a couple parts suppliers, the Bilsteins are not as high pressure as the Fox but are still better than the stock shocks. The more info I gather, the Fox are great for the offroad applications that provide constant abuse, but the Bilsteins are much more comfortable on the road...but do give up a bit of heat dissipation ability offroading.
Lift: Tell us about your lift. Spacer or spring up front? New leaf pack or block in the rear? Which engine does your truck have, 6.2 or 6.7? All of these will affect ride quality and comfort. If you have the 6.2, its more than likely that the springs are too heavy for the truck. The 6.7 diesel outweighs the 6.2 by 700-800 pounds and requires heavier weight springs. Also, has a new track bar or drop bracket been installed?

 

Stock F350 SRW 4x4. 265/75r16 BFGs. 65F 75R. Lots of unladen hwy driving.

 

So are you saying you run at 62 PSI all of the time? If so, do you have your truck fully loaded to capacity all of the time? If not, then why run at the higher pressures when it's not needed?

And I agree about the tires. Also a taller sidewall tire will help soften the load as it helps work as part of the suspension. so a tire on a 15 or 16 inch rim will have a larger sidewall than a 20 or 22 inch rim with the same overall size tire. That extra sidewall will flex some as the suspension flex's. We run 40" tires on a 17" rim on a off road race truck that will do 140 MPH across the open desert. That tire flex is considered in the design of the suspension some.

Shocks and springs work good as a package. Saying a Fox shock is stiff because it is used offroad is a misnomer. It all depends on the valving. I have king shocks on my K5 Blazer and they are valved to the weight of the truck. It's a soft ride thru town and is actually smoother than my F250. And I can take it to the dunes and jump it and it still has a soft landing.

Our trucks are 3/4 ton trucks, so the spring/shock package is going to be stiffer than a 1/2 ton truck because it's designed to hold a heavier load. Put a full load in the truck and it will ride better. take that load out and it's going to be stiff.

Lift the truck with springs from any basic company and it's going to be a stiffer ride.

Lift the truck with springs from a company who designs them for the intended use and they will ride better.

My Blazer has Deaver springs on it and 5 inches of lift. The front stock spring pack was 2 leaves, the Deaver spring pack is 14 leaves, but the leaves are thinner than the stock ones. The stock spring pack had about 3 inches of total travel, the Deavers, 12 inches of total travel. Big difference.

 

Yep, rides just fine with 62 PSI. I've experimented with lower PSI's and honestly, for a daily driver it's just more hassle to air up and air down if I'm towing or hauling anything. The 62 PSI is a comfortable ride and still allows max load. If you drive a Honda Civic, do you change the PSI based on how many passengers are in that vehicle with you?

I do agree that the shocks and springs work good as a package. In this case, we are assuming a few things that we don't know. 1. He runs the 6.2 that's significantly lighter than the 6.7 and his rough country lift has springs for the diesel = Stiffer. 2. He's running Fox shocks. Likely the entry level 2.0 that apples to apples are stiffer than Bilsteins. The valving is different in the 2 shocks and reviews show that the Fox are stiffer because of their valving and charge. I do agree that Fox shocks are butter smooth on the right application....in this application they are probably not the right shock for the already incorrect spring rate for the weight of the truck.

Agreed! My truck has the stock suspension and rides good for being an empty 3/4 ton....rides like a Cadillac pulling my travel trailer. The biggest turn off to lifting my truck is compromising the ride quality with cheap parts. It will stay stock height (except replacing the shocks) with the softer front springs for the 6.2 unless I go to a 2.5" lift. If that's the case, it will only be with the Carli commuter package. They make springs specifically for the light weight front end and run tuned shocks for best ride quality. Put that same system in a 6.7 and it'd likely drive like a boat!

 

Rough country lifts are stiff that's for sure. Mine already had the rough country level on it when I bought it. I had been looking for a 2" level lift but can't seem to find one that's all new springs, just add a leaves to the stock springs, which I don't have. Only other choice is a 2 1/2" lift.
So I went and added a 1/2" block to the rear to level it off. Now that I've done that, I'm going to go back and see if I can find a good 2 1/2" level lift for the front, hopefully with Deaver springs as I like them.

Changing the shock valving is really not that hard to do. Filthy motorsports has a tutorial on their website on how to do the king shocks, which are basically the same as the Fox. I rebuilt my Kings and changed the flutter stack around on the front shocks to make the initial hit on stutter bumps a little softer. The nitrogen charge is more to prevent foaming of the oil. But it can be used to fine tune that last little bit in a race shock after everything else had be done. For a street driven truck, its there just to keep the oil from foaming as we don't push out trucks that hard to need to adjust the pressure. My Kings ran at 250 PSI which is factory recommended.

As for tire pressure, I leave mine at 35 until I get ready to tow or carry a heavy load a long distance, which is about 10 times a year max. Driving the 5 miles home from Home Depot with 2500 lbs of concrete wasn't a issue.

Carli, Deaver, Icon, and maybe Atlas are probably the best spring packages out there for a comfortable ride. King, Fox and Bilstine are the main shocks, there are a few new comers to the scene that are showing promise, ADS racing shocks. The other brands I don't think have kept up with technology.

Here's a interesting useless fact for you.
Race truck weighs north of 6000 lbs fully loaded race ready.
Tires are BFG 40X12.50 17.
We run them at 26 PSI when we put them on. After about 200 miles when we change them, the pressure is up to between 35 and 40 PSI, depending on if it was a slow or fast section before getting to the pit.

 

On my 2001 diesel door tag says 60 front 80 rear
I run 70-75 front and 80 rear.

I always like to run my tires near max pressure, that' s why my old explorer never flipped over due to Fire$tone tire failure$.
My tires never failed while driving the Explorer, but one day parked in my garage, I did notice one did have major tread separation.

 

2016 F250 6.7L
275/65R20 E Rated Toyo AT2




Currently have 46k on the tires with most of the miles with 55 in all 4 corners and they are wearing fairly evenly across the tread width.
I pull a 6500 lbs landscape trailer around that has a 1000 lbs tongue weight 95% of the time. My front axle is 5k and the rear is 4k with the trailer connected. Only reason the rear is currently at 60 is for hauling mulch in the bed of the truck.

 

That is good to know that they are wearing evenly and you use the truck for hauling. With your tires at 55 psi, they have a load rating of about 2850 each. Your tires can effectively carry 11,400 lbs, well over the 10k GVWR on your truck. Right on!

One question I do have, do you notice a big difference while towing between 55 and 60 psi?

 

I run all of my LT tires at 80psi. They ride a little rough but it's not a car, it's a truck. You also can't just add up the load for all four tires and say that you're good for the weight that you're towing. With my Gooseneck on depending how it's loaded I can be over the tire weight on the rear axle and not even close on the front.

 

I don't notice any difference while towing the landscape trailer at either of those psi. 60 psi does make towing the 8k camper feel more solid.

I installed air bags earlier this year and even with 5psi in the bags the ride is slightly harsher unloaded than before the bags.