Ford recommends running 55psi front and 70 psi in the rear. What psi are you guys running in your tires? I'm running stock size 265/75/16 e rated

 

I go off of what the side wall says and add 5psi. for long road trips and take away 5psi for dirt, or snow covered roads. That's just what I do. I have on board air so its a little easier for me to play with it.

 

Right now Im running 70 all the way around and my truck bounces at 35-40 mph. Should I drop tire pressure to 60 or is my truck bouncing because they are load range e?

 

Not a 100% sure about the load range being E, what does the tire psi cold say on your tire sidewall? I'm running a 35" tire load range D at 50psi. Different tires, sizes, and load ranges call for different psi. 70psi sound a little high to me but again it's all about what your specific tire sidewall says. It's in a small print on the sidewall should say something like maximum weight at whatever psi cold. Go to your specific psi and play a little from there. To much psi will give you rougher ride, and less psi will give you a bit of a smoother ride but bad tire wear. I wouldn't recommend going less than 5psi of your tire rating as the cost of tires are insane like fuel, but thats a whole different topic.

 

Check the sidewall for max. I have E rated for the winter tires, and run 55 front, 35 rear (unloaded). Seems to get good wear from the Michelins.

 

I'll have to check on the cold max but the max is 80 psi

 

I run 60psi all the way around.

 

If you can produce the real axle weights , or better real seperate wheel( pair) weights, in the loading you drive, I can calculate the needed pressure for that with a sertain reserve for things like , pressure-loss in time, Unequall load R/L, misreadings of weight and pressure schales, and what I might have forgotten.

If you dont have those , we will have to do with the GAWR's ( gross axle weight ratings) front and back, asuming you are not allowed to go over them, but for rear is often done.

For that I use my motorhome-tire-pressure-calculator, in wich I use my own formula , that takes better care then the official formula's , that the deflection of the tire stays the same as when maximum load and that pressure on the sidewall on the tire, and so its allowed to go verry low in the pressures.
Also I add a reserve depending on if GAWR or real assumed weight is given.

Then if the tire-maker gave a maximum load that is save to natural laws, my advice is save.
But for some tires, in this case the off-road kind of tires with large profile blocks covering a part of the sidewall, this maximum load given on sidewall is to high. So you have to yudge that and write it too so I can yudge how much has to be substracted of the maximum load.
In the Ford/Firestone affaire, I suspect the tires to be that kind of tires wich the maximum load should have been substracted a part to be right to laws of nature.

But for this reason the pressures are kept pretty high after 2000.
And probably you can do with lower on the back when empty.
But to be shure we have to calculate.
Front does not have to be higher , the load does not get more when loaded, because most is loaded at the back, even behind the back-axle.
If front needs to be higher then 55 psi, it is because the original advices are made with a formula that is still used in America , but leads to to much deflection in the lower load/maxload ratio.

So to make a long story short, give the details and I will calculate.
Your tires in a list of Toyo gave 3415 lbs single load at E-load/10PR for 80 psi.
This 80 psi is not the maximum pressure of the tire, but the pressure needed for the maximum load to drive up to maximum speed of tire for up to R speedrated LT tires. If higher its for up to 160km/99m/h.
So you are allowed to go over that, as scottahoe writes to do with his 5 psi.
For in sand you may even go lower, somethimes even half of the pressure calculated is used. This can be done because of the lower speed and the different bending of the tire in sand.
Probalbly you dont need to go that high because of the pretty oversised tires for the weight of the car and axles, but this is quessing.

 

In daily driver mode I'm running 55 all around on oe size Bridgstone Revo 2, wearing flat thru the last 3 rotations. Still rides like a conestoga, but better. Towing I'll go up to 70 in front and 80 in the rear. Ride is much nicer with the weight on it.

 

I'll have to assume the door sticker tire psi is loaded. I'm gonna try 55 psi all four tires

 

Thats a good plan. I was trying to match sidewall bulge front and rear, with front at 55. Even with the rear at 35, the empty box does not quite have the weight to bulge the sidewalls the same, but it's close.

Do you run empty most of the time? If it's mixed loading of 1000-2000lbs, 55 in the rear is a good call.

 

Yes empty majority of the time

 

Ok, you could just run 55 all around, and do your rotations as needed to keep wear in check. Then you're ready to carry a medium load without having to air up. I was trying to soften the ride a bit too by going to 35 rear.

 

How was the ride with 35 in the rear?