My F-150 was a 2009 SCREW. It was much smoother riding, but like I said I knew beforehand the 250 was sprung tighter. The difference is noticed mainly on railroad tracks, potholes, and most severely on rougher dirt roads. Smooth highway is not bad. It is my wife who notices it much more than I do, although I also perceive a noticeable difference.

I have about 9,000 miles on it and have noted no difference from day 1. My Ford dealer, a friend, suggested putting more weight in the bed. Not a great solution as far as I am concerned. I incidentally had a rental Ram half ton crew in Dec in NM, and while I have no intention of switching, it was the best riding truck I have even been in. That sucker was smooooth! I never adjusted to the dash mounted gear **** though (another topic).

 

My F-150 was a 2009 SCREW. It was much smoother riding, but like I said I knew beforehand the 250 was sprung tighter. The difference is noticed mainly on railroad tracks, potholes, and most severely on rougher dirt roads. I mean a body could lose some dental fillings on some of them! Smooth highway is not bad. It is my wife who notices it much more than I do, although I also perceive a noticeable difference.

I have about 9,000 miles on it and have noted no difference from day 1. My Ford dealer, a friend, suggested putting more weight in the bed. Not a great solution as far as I am concerned. I incidentally had a rental Ram half ton crew in Dec in NM, and while I have no intention of switching, it was the best riding truck I have even been in. That sucker was smooooth! I never adjusted to the dash mounted gear **** though (another topic).

 

That's a great story, but without references, that's all it is.
I have very carefully reviewed all the documentation I have concerning my truck, it's tires, and the amount of air to put in them. Nowhere did I see the word "suggestion" or anything akin to it.

I'd really like to know where folks are getting this idea that these specifications are recommendations.

 

As requested. Lots of great information out there if you only take the time to access and absorb it.

https://images.search.yahoo.com/imag...hspart=mozilla

As you can see, recommended tires pressure values change based on the tire specs and the load carried.

 

I have the standard gas suspension and my 250 rides almost as nice as my 150 did. But then the 150 had E rated tires. I think ride quality has a lot to do with the tire type.

Anyway, I run 65 psi all around all the time.

 

I think the concept of reference material is escaping you. Your link shows a rather official looking chart that was posted on a forum for full sized Broncos. It doesn't in any way convey information certified to be accurate by any manufacturer.
On the other hand, I took the time to access Michelin USA's website and absorb information provided by them, an actual tire manufacturer. Here's what they have to say about tire pressure:
The vehicle manufacturer selects the size and type of tires for their vehicles. They perform the necessary testing to establish the vehicles’ optimized operating tire inflation pressures which can be found on the vehicle placard (located on the inside of the driver's door) and in the vehicle owners’ manual.
If the tires on your vehicle are the same size as the original equipment tire, inflate them to the pressures indicated on the placard.
Seems pretty straight forward to me.
They don't say anything about running at different pressures. They don't say the pressures on the placard are recommendations, optional, or based on the zodiac. In fact they specifically address lower pressures with this:
Lower inflation pressures for improved flotation are permitted ONLY if the tire maintains adequate load-carrying capacity at the lower pressure. 20 psi is the minimum recommended pressure for a passenger or light truck tire. Pressures lower than 20 psi may be used off the road when speeds are less than 15 MPH and when the tire has adequate load-carrying capacity at the lower pressure.
The best recommendation for highway use is to follow the inflation pressure specified by the vehicle manufacturer which can be found in the owner’s manual or on the sticker on the inside of the driver’s door.
When installing a different size than the original equipment tire, the replacement tire should be inflated to provide the same load capability of the original tire size at the manufacturer’s recommended pressure.

 

Thanks wrvond, your red insert pretty much supports what I said.

Lower inflation pressures for improved flotation are permitted ONLY if the tire maintains adequate load-carrying capacity at the lower pressure.

I`m all about data, the science, formulas, validity and reliability co-efficients so the concept of reference material is not as foreign to me as trying to teach pigs to dance. For the record, here`s some reference material you may find interesting.

http://www.dawsengineering.com/linke...ducedloads.pdf

Let's simplify this. Two important pieces of information are needed. The vehicle manufacturer's specifications and the tire manufacturer's specifications.

The vehicle manufacturer provides information on recommended tire size, load ratings etc. for a specific vehicle in addition to the vehicle's weight specifications i.e. front and rear axles carrying capacities, gross weight/carrying weights etc. This information is found in the operator's manual and on the door pillar label.

The tire manufacturer provides information like tire size, load and speed ratings, date of manufacture etc. The manufacturer doesn't usually care (there are some exceptions with small production run, vehicle specific tires) what make/brand of vehicle their tires goes on.

I included the chart as an example to illustrate an "E" load rated truck tire has 10 plies (an industry standard) and varying psi values depending on the weight each tire would be carrying. It doesn't matter if the tire is mounted on a Bronco, RAM or Yukon ... it is a tire industry standard ... not vehicle make or brand standard.

People vary tire pressures with the same tires all the time based on their specific driving application and the weights they are carrying (or not carrying). If my tires can safely carry my truck, me, my fuel and my load at a reduced psi rate (as outlined in the chart) then I will use the lower psi value as it usually means a softer, less harsh ride.

https://toyotires2-1524598101.netdna...s_20151020.pdf

When I load up my truck (i.e. when I carry my truck camper), I inflate the psi value accordingly to accommodate the increased weight I`m carrying. And yes I weigh my truck and know its empty weight (gross, front and rear axles) and it`s fully loaded weight including people, fuel and equipment.

So if you feel better running at exactly what your door sticker says regardless of the load you`re carrying ... then fill your boots. I, along with many others, calculate a load specific psi value and that`s the number we inflate our tires to ... just like your quote states it`s OK to do.

We know vehicle manufacturer`s cover their legal butts and try to make things easy by posting specific psi values for tire inflation as many people don`t pay attention to or don`t understand this stuff. Those people need a firm inflation number to keep things simple for them and to keep them out of trouble.

 

So I have an 2014 F250 CC 4x4 6.2 with no special spring packages and I hate the way it rides.

I know it is a 3/4 ton truck, but that doesn't change the fact that I wish it rode better when I didn't need it for its purpose. I can't have it all.

I run my tires at 65psi when I am not towing or loaded heavy, but there is no comparison to my 1500 or a F250 with the diesel. The part I am confused about and will be forever is my truck sags like crazy when I am loaded or Towing but still rides like garbage.

 

I went by a my Michelin dealer, who is a large outfit and sells a lot of both passenger and commercial tires. I was told 50 psi was probably OK, but not advisable to go lower. He also said my low pressure light would very likely come on. I do not want that as it would not only be annoying but dangerous as I would not know if a tire was really going flat.

At this point I remain somewhat confused. I can't imagine dropping down 5 or even 10 psi would make a huge difference in ride quality but I will start there. I don't think it will hurt.

I run 4 (four) psi in my Kawasaki Mule and it is still a bit of a rough ride. I don't have access to any scales, but I suspect the Kawa is a bit lighter. I guess one thing to keep in mind is that an "empty" 250 6.7 is still a very heavy vehicle!

This post has been quite informative despite some opposing thoughts. Thank you all for your research and input. I think we have a very good forum here.

 

Good luck NNM and post up to let us know how it went for you. Always good to close the loop so we can learn from each other. BugJr

 

Mike, earlier I suggested using the chalk method to determine proper inflation, but now I want to retract that and here's why-
I learned that method from a car magazine back before there was even such a thing as radial tires. It worked really well back then but tire technology has not sat still in the intervening years. What worked then really shouldn't be indiscriminately applied today. There are more vehicles on the road than ever before travelling greater distances at higher sustained speeds. Safety is paramount; we owe it to our families, to the other people on the road, and to ourselves to adhere to safety related requirements. It is apparent that there are many people that think they know better than the actual experts as well as people that just don't know better. TPMS wasn't made a legal requirement because some senator thought it'd be a really nice option. It was based on the huge numbers of people driving around on under-inflated tires and the numbers of accidents each year that could be attributed to that. I know this because I read the legislation and reference material, not because I heard it somewhere, read it on some forum, or guessed. Sunavabug has taken reference material out of context and cited other reference material concerning establishing pressure for non-OEM tire sizes claiming this supports his position that it is ok to run low pressures on the highway. This couldn't be further from the truth. The evidence has been presented to establish that and your own experience talking to the dealer supports that. I used to drive a Jeep off road nearly as much as on road, neither I nor my compatriots aired down while still on hard top and we never drove on hardtop until we had aired back up. Another good example are OTR truckers. These guys make their living driving long distances in big trucks with big, really stiff tires. You'd think that if there was any comfort to be gained, if it was safe, they'd be the first to air up and down dependent on their load. But they don't. Those tires are set and maintained in accordance with set requirements.
I know you want your bride to like your truck and to like riding in it with you, but it's even more important to be safe.

 

Here's a question. The sidewall always says the recommended pressure is to be checked cold.
So does this mean they've taken into consideration the increase in pressure at highway speeds? I would assume they have to avoid over inflation and premature center tread wear.
In the meantime I'll continue to go with what Ford says. Sure it rides rougher than any of my past F150's. But I moved up to a SD for a reason and expected this.

 

Just a side note - For every 10 degrees F, Your PSI will change exactly 1.

 

Now you are opening a whole new can of worms!
I would say yes, it's accounted for in the design standards. One thing you need to know is - what is this "cold" they are talking about? The short answer is it is 68 degrees F.
A good rule of thumb is that pressure varies 1 PSI for a temperature change of 10 degrees Fahrenheit. So, if you measure your tire pressure at 90 degrees Fahrenheit ambient, the "standard" pressure at 68 degrees would be about 2 PSI less than what you measured. If you want, say, 44 PSI at 68 degrees, but it's 90 degrees outside, then adjust tire pressure until the gauge reads about 46 PSI.

 

Yes, the change in pressure is taken into account as a tire will heat up some after driving. I feel certain of that and see it on my passenger car that has pressure monitors with digital readout on the dash.
A current trend is to use nitrogen rather than air (which is 78% nitrogen anyway). It reportedly doesn't heat up as much as air and leaks out to a lesser degree with time.

I don't use it because I have access to air compressors both at home and on the road. I have seen nitrogen only at the larger dealers. It is also costly. My car came with it but I use just air when it get low.

This has no direct bearing on the topic of course, I just though I would throw that in to add to the confusion.

As wrvond correctly pointed out the primary consideration is SAFETY. All else is secondary.
I feel a bit more research on my part is needed.