They don't really just stiffen the suspension, they absorb the shock of hitting the bumps. Running empty I run 5 psi on them but when I hook to our rv I raise them up to around 20 psi. You would be amazed at how much the air gauge for them bounces around even with the truck empty.
The springs bottoming out wasn't causing a rough ride just an annoying noise every time you would hit a bump.

 

That is what I did and they are the best tires I have ever had.

 

I second what Larado350 says. Most every tire mfg provides weight/pressure scale fo single and dual applications. If you run your rig onto the scales loaded and unloaded you would be amazed at the difference in acle weights and it only makes senme to follow tire mfg guideline, maybe adding a bit if you want a harsher ride. Otherwise you ride harsh all othe time that you are empty and will wear out the center of tires - probably not noticeable tire war if you carry modest loads most of the time. My reason for pointing this out is I have a Job 1 450 and when it is loaded I need to have 10 pounds OVER the pickup plackcard suggested inflation to match my load. That load is well under weight rating of rear axle, yet pretty close to the rating of the front axle - but not over the tire ratings or max pressure when I follow the inflation pressures guidelines bt tire mfg.

John

 

Thanks Bill, Crazy001, and all the others here who realize that the manufacturer of the VEHICLE sets the reccommended tire pressure, based on the axle weight, unloaded. As stated in this email I received from an engineer at Michelin, "When your vehicle was manufactured, Ford selected the appropriate tire,
based on the axle weight.

Then knowing the actual axle weights they determine the air pressures of the
tires.
The 65 psi is based on axle weight, does not including any hauling, towing,
etc.

So we have to give you the standard answer..........door placard, anything
lower subjects the tires to overloading and the possibility of sidewall
ruptures."

So Laredo, what have we learned? These are heavy trucks, and as has been stated by MANY here, they've run their tires at 65 and EVEN higher with no problems. Kind of reminds you of the days when the Ford Explorers were blowing out tires because of low tire pressure. These are 10 ply tires and they need that amount of pressure to stand up to the stresses/weights, unloaded, like the email above said. Running anything lower or trying to find a tire manufacturers reccomendation for a certain weight just wont work because they have to factor in what the vehicle axle weighs. There are max pressures imprinted on the sidewall, but that doesnt mean you use that for everyday driving. Class dismissed Laredo, and thanks to all of you for your comments. We all come here for help and guidance, reccomendations, and there's no sense in someone blowing their stack 3 posts down. By the way Bill, have you gotten that hybrid out of your grill? :-)

 

There's no call for the jabs and personal attacks. Keep it civil.

 

Hmmmm Amazing,,a 3/4 ton vehicle's ride is firm !

You should ride in a Older F-250,,say a 75' or so,,,or and older Dodge,,,,Thats a rough firm ride !

My 18" Contis have had 80 psi in them since I drove the truck home over 3 yrs ago! Rather loaded all the time plus towing trailers.
The ride in my 06' F-350 is not that bad comparing to other trucks (older)I have been in.

 

Have read on here for years how much better Mich's are than stock....
I just swapped from the stock BFG's that I got 84k miles out of (with tread left) to Michelin's and I am really under impressed.....

IMHO, the ride is very similar to the bfg's re jouncing over bumps, etc...
so the tire only has so much to do with it.... after all, load range e's are load range e's

I too adjust my air pressure based on intended usage....
but not having a scale at the house, I use the chalk test to gauge the load on the tires....

When we use the Ex for our trips, I will bring my handy dandy B&D air station along...
Air up for the long interstate rides to 75 or 80 cold (even if not towing)
and once we get to our destination, air them down for the running around on the secondary roads.....

then use the air station to bump them back up for the long ride home

(I fool myself into thinking this will get me better mpg @ 80 - 90 mph keeping up with traffic )

to heck with the .5 drag coefficient !!!!

Good luck....
John

 

Air Ride Suspension

See Mine Below, rides like a Cadi Empty and can make it ride level w/ ~5,550# on the rear axle.

 

That is awesome!
Do you have a thread detailing the swap?

 

Thank you! Detailed Swap=Forthcoming. When I get back from this trip (Wed.) I should have all the photos & video organized.