How much air in the tires? Need advice... First "real haul"

I run my 19.5's at 75 psi front and 90 psi rear. I have tried different numbers but for my weight I find the truck handles great at these numbers. When I had my regular tires on I ran at 80 psi. I have no extra weight on my front end with camper on so I questioned why I added the extra air to the front.

Paul

If you need an engineer to explain tire pressures, just read the door placard on your vehicle. The placard on my dually says to inflate tires to 65 psi at maximum rated load which if I recall is a little over 9000 lbs. I would assume that an engineer came up with this number. So why should I disbelieve him and run 80 psi?

ryoung

Run the recommended 65 in my rears on my dually. Seems to work well. I'm just under RAWR and GVWR.

Back to the question..... I keep my rear tires at the door sticker recommended 70psi, but within a half hour of driving with my overloaded TC the tire sensors show 80psi. Seems about right, but I wouldn't want to start out at 80 and go to 90. I'm wondering if folks with 19.5's see their pressure go from 110 to 120psi?

sleepy wrote:
Where do you haul thge air compressor... changing air pressures in your tires as you change roads... bull!

We usually travel 3 to 6 months and more than 20 states... US highways and dirt roads... everywhere and we have been doing it for 40 years. All of 7 of my tires were changed at Sams in San Angelo Texas at 47,000 miles using the same brand of tires that GM puton it originally. They were all within 1/32" of each other on tire tread.... I rotate them all including the spare.

We have engineers on this site... but all engineers don't work with tires, or electronics, or aerodynamics... .

We had a Doctor in East TN doing gynological exams... he got caught and was prosicuted... he was a Dr of Dentistry... maybe we should get him to explain tire pressures to us.

AS I explained to the OP... you'll get a bunch of theories... make it easy... just don't exceed the side wall limits.

A huge advantage of the maximum pressures it reduces the sway and wobble from squishy tires.

Chet

I don't change air on the road even though I do carry an air compressor when I'm on the road. I meant when the camper is going to be off the truck for extended periods of time at home. I also have 2 big air compressors at home, one in the main garage and one in my shop so it is not a problem. If your not overloaded on your rig then you are not going to have sway with the recommended PSI. I run 65 PSI and I have no sway with my rig but as stated I have over 2000# extra capacity on my truck before I reach my GVWR. I don't have a rear sway bar as I don't need one either.

Just because somebody doesn't happen to agree with you it is bull in your opinion, I'm sorry that I don't happen to agree with you on everything but I guess I need to bow down to your superior knowledge and accept you are always right so it must be bull.

I BOW DOWN TO THE SUPERIOR KNOWEDGEABLE ALL KNOWING PERSON AND EXCUSE ME FOR HAPPENNG TO DISAGEEE WITH YOU. IT WON'T HAPPEN AGAIN.

Now the above statement IS full of bull. I happen to have my own opinion and have a right to it without it being called bull.

And furthermore I did not say I change tire pressure as I change ROADS as you stated I said I change tire pressure when I'm unloaded meaning at home after a trip.

Did you go and look at the posters link I suggested. He IS a tire engineer and has been one for over 30 years. The posters signature is CapriRacer, take a look and read some of his information at his link in his signature if you are willing to maybe learn some new stuff and maybe find out there are other ideas and those people are TIRE ENGINEERS.

You know I get really tired of you and your thinking you are the only one on here that knows anything. I have a suggestion for you, why don't you take a sabbatical from here and write the new book of knowledge as you know everything.

Sleepy, just to let you know I have been around the block a few times also and have had a lot of experience and have been Rving for over 40 years in everything from TC, 5ers and even to diesel pusher MHs so maybe I might know a little bit also. Why do you think the tire companies put out a suggested tire pressures chart. Someone went to a lot of work to figure this out and I don't think for one minute that the tire manufacturers are going to spend that amount money if they don't feel it is needed.

Wayne, I know this is an attack towards an individual so you can ban me or delete this post if you so wish, that is up to you and admin. I'm just sick and tired of Sleepy being combative to people that don't happen to agree with him. It gets to the point that people are not going to post a difference if Sleepy has made a statement that they don't agree with as he always attacks them and their idea.

sleepy wrote:
Where do you haul the air compressor... changing air pressures in your tires as you change roads... bull!

AS I explained to the OP... you'll get a bunch of theories... make it easy... just don't exceed the side wall limits.

A huge advantage of the maximum pressures it reduces the sway and wobble from squishy tires.

Chet

My response was based on having a SRW truck and when I had the Outfitter, I did change air pressure based on changing road conditions. Yes, it was a PITA, but I wasn't just going down forest service roads either when I lowered the pressure.

I carry a Viar 450P air compressor everywhere I go with a tire repair kit. Now that I have a heavier camper, I think my tire pressure changing days are over.

Where do you haul thge air compressor... changing air pressures in your tires as you change roads... bull!

We usually travel 3 to 6 months and more than 20 states... US highways and dirt roads... everywhere and we have been doing it for 40 years. All of 7 of my tires were changed at Sams in San Angelo Texas at 47,000 miles using the same brand of tires that GM puton it originally. They were all within 1/32" of each other on tire tread.... I rotate them all including the spare.

We have engineers on this site... but all engineers don't work with tires, or electronics, or aerodynamics... .

We had a Doctor in East TN doing gynological exams... he got caught and was prosicuted... he was a Dr of Dentistry... maybe we should get him to explain tire pressures to us.

AS I explained to the OP... you'll get a bunch of theories... make it easy... just don't exceed the side wall limits.

A huge advantage of the maximum pressures it reduces the sway and wobble from squishy tires.

Chet

Butch has it right. Why deliberately disable an important part of your suspension, and reduce traction, handling and overall safety, by running tyres harder than they need to be according to the tyre manufacturer's recommendations.

In addition to that setup - which covers running at maximum rated tyre speed on paved roads - I have another set of pressures whenever I get onto gravel roads. That is reduce the pressure to 80% of normal and drive at a maximum speed of 50mph. If the roads are badly washboarded or rougher, then the pressure goes down some more and the speed goes down accordingly.

I use the same methodology in setting pressures on all vehicles - from the 17 ton bigrig down to the little Suzuki

I don't agree with the just run max on the tire. If it is not needed there is no reason to run it.

On my dually with 65PSI (RECOMMENDED PSI) the rear axle is rated for 9750 RAWR. My rear axle empty is 3300#. Loaded with my camper ready to go the rear axle weighs 7200#. So with the math I have 2550# of reserve capacity on the rear axle with 65PSI. Why would I need to run 80PSI?

If I raise my rear tires to 80PSI than I would have 11332# of capacity on the rear axle. Each tire on my truck in dual setup is rated at 2833# at 80 PSI this equals the 11332# stated above. This would give me a 4132# more capacity on the rear axle. Why do I need that much?

Unless you are running over the RAWR on most duallys there is no reason to have 80 PSI in a dually. I'm talking on the 3500/3500 series not the 450/550 with 19.5s.

If you are running a SWR than your RAWR is rated at 80 PSI. Most SRW with a camper are going to have to run the 80 PSI.

I would follow what the tire manufacturers have on their load charts. They have a little more experience than we do with their tires. Run what is recommended + a little more just for comfort reasons plus that is the minimum to carry the weight but just because it states 80 PSI does not mean that is what you have to run. That is the tire manufacturers have stated that it the MAX tire pressure and the given rated weight the tire can carry at that PSI. It is not saying that is what you must run.

For the fellows with SRW do you run 80 PSI even if you are running around empty most of the time? On my SRW when I was empty and not on a trip and just unloaded for a few days I would lower the rears to around 60 to 65 unless I was going to carry a load.

Take a look at CapriRacer link he has in his signature. I did and he happens to be a tire engineer. I think what he has written is well worth the read and to heed his advice. The guy has made a living at doing this for over 30 years.
This is IMO

The tires on my dually don't get too many miles before I have to replace them. We haul thousands of pounds of steel monthly for our business in this truck. I usually replace every other year.