Proper PSI for unloaded truck with range E tires?

[JHZR2]

My 96 Dodge Ram trucks run 245/75-16 tires. They are load range E.

Door placard says to run them pretty high pressure. Of
Course it’s assuming that the truck will be loaded to max.

If I am going to run much at low/no loading, should these be reduced? I certainly don’t want under inflated tires. I can understand and appreciate that the right thing to do would be to verify the contact patch, however, that may be flat only at a psi that is indeed too low for the tires.

Do load range E tires have a minimum inflation value? The sidewall doesn’t say.

I know that @CapriRacer lined to a tire pressure site, and I looked at the chart. My 4x4 ram has slightly larger tires, the PO put 265/75-16 tires. So that chart shows:

KBB (FWIW) says my curb weight is 5005 lbs. So figure with 36 gallons of fuel and 350lb of riders, it’s really more like 5600-5750#.

So what’s the right unloaded pressure?

 

[wwillson]

@CapriRacer is our tire expert

 

[bullwinkle]

My 96 Dodge Ram trucks run 245/75-16 tires. They are load range E.

Door placard says to run them pretty high pressure. Of
Course it’s assuming that the truck will be loaded to max.

View attachment 236881

If I am going to run much at low/no loading, should these be reduced? I certainly don’t want under inflated tires. I can understand and appreciate that the right thing to do would be to verify the contact patch, however, that may be flat only at a psi that is indeed too low for the tires.

Do load range E tires have a minimum inflation value? The sidewall doesn’t say.

I know that @CapriRacer lined to a tire pressure site, and I looked at the chart. My 4x4 ram has slightly larger tires, the PO put 265/75-16 tires. So that chart shows:

View attachment 236884

KBB (FWIW) says my curb weight is 5005 lbs. So figure with 36 gallons of fuel and 350lb of riders, it’s really more like 5600-5750#.

So what’s the right unloaded pressure?

The best way is to put the van on a scale and see what your front axle & rear axle weights are, and adjust accordingly. Different LRE tires will have different load carrying characteristics as well-for instance, the soft OEM Continentals on my heavily loaded Transit 250 actually required LESS PSI to stop from wearing out the centers rapidly, ant the Cooper Discoverer LT3s that are on it now need max pressure of 85 PSI in the rear to prevent the rear from getting frisky due to weight+tread depth. A good example for OP is my Express 3500-it usually is fairly empty except for occasional hauling of scrap, etc.-it gets 55 front, 65 rear empty, 80 rear loaded (Hankook LT245/75R16 RT03s).

 

[RhondaHonda]

I’d run 50 in the front and 40 in the rear and see how it rides.

 

[wwillson]

I’d run 50 in the front and 40 in the rear and see how it rides.

What is your reasoning?

 

[bullwinkle]

My 96 Dodge Ram trucks run 245/75-16 tires. They are load range E.

Door placard says to run them pretty high pressure. Of
Course it’s assuming that the truck will be loaded to max.

View attachment 236881

If I am going to run much at low/no loading, should these be reduced? I certainly don’t want under inflated tires. I can understand and appreciate that the right thing to do would be to verify the contact patch, however, that may be flat only at a psi that is indeed too low for the tires.

Do load range E tires have a minimum inflation value? The sidewall doesn’t say.

I know that @CapriRacer lined to a tire pressure site, and I looked at the chart. My 4x4 ram has slightly larger tires, the PO put 265/75-16 tires. So that chart shows:

View attachment 236884

KBB (FWIW) says my curb weight is 5005 lbs. So figure with 36 gallons of fuel and 350lb of riders, it’s really more like 5600-5750#.

So what’s the right unloaded pressure?

245s will be lower-a normal max weight @ 80 PSI is 3042 lbs.-adjust downward accordingly. Some vans can handle 265s rear-I’ve ran them on a diesel F-350 SWR cargo van before.

 

[bullwinkle]

I’d run 50 in the front and 40 in the rear and see how it rides.

I’ve never heard under 45 recommended, would have to be a completely empty pickup. Even an empty van body would weigh enough to need 55 minimum.

 

[RhondaHonda]

What is your reasoning?

Looking at that chart with the pressures and load capacities and I was assuming a dually from what I thought I had seen a pic posted of before.

If loading heavy, then I’d bump the pressures up but the fact that he is even posting the question shows he’s more concerned than most would be and would likely notice unusual wear, high temps, or bulging if pressure was too low.

 

[RhondaHonda]

I’ve never heard under 45 recommended, would have to be a completely empty pickup. Even an empty van body would weigh enough to need 55 minimum.

I thought this was a DRW Ram pickup. The bed weighs almost nothing and daily driving empty is not taxing 4 load range E tires out back.

 

[MParr]

With 80 psi in the rear and no load, that truck is going to get squirrely in the rear.

 

[JHZR2]

I thought this was a DRW Ram pickup. The bed weighs almost nothing and daily driving empty is not taxing 4 load range E tires out back.

This is a SRW Dodge Ram Cummins pickup. One is 2wd, one is 4WD.

I provided approximate curb weight.

Based upon the chart, I could run 35 psi. The truck isn’t 7500lb unloaded. And I’m not saying I should run 35. But I suspect the necessity of running 65/80 is also not there.

 

[bullwinkle]

I thought this was a DRW Ram pickup. The bed weighs almost nothing and daily driving empty is not taxing 4 load range E tires out back.

Didn’t realize it was a pickup, but 45 would be nothing in the bed. Even when I ran my ‘06 Ram 3500 SRW I ran 55 in the rear with just the cap on it (but it was a Cummins 4X4 short bed MegaCab, more weight on rear empty). Seen a lot more tire failures from too little PSI than too much!

 

[bullwinkle]

This is a SRW Dodge Ram Cummins pickup. One is 2wd, one is 4WD.

I provided approximate curb weight.

Based upon the chart, I could run 35 psi. The truck isn’t 7500lb unloaded.

My ‘06 was just over 7000 empty, maybe the older ones were lighter? I would still put it on a scale…

 

[I<3oil]

I usually run 55 all around when not towing. Under 54 and TPMS throws a fit.

 

[cptbarkey]

I usually run 55 all around when not towing.

This is what I do. If towing i'll probably do 5 under max due to heat expansion.

 

[wwillson]

This is what I do. If towing i'll probably do 5 under max due to heat expansion.

Ignore heat expansion and run max sidewall pressure when towing. Tires are made to run at max sidewall cold and whatever pressure they expand to when operating.

 

[I<3oil]

This is what I do. If towing i'll probably do 5 under max due to heat expansion.

Yup. Right now they’re at 75psi cold as our camper is hooked up.

 

[Big E]

I had the exact same truck as the op for 20 years. I ran 60 in the front and 45 in the rear when empty. I used to commute with it, so plenty of freeway speed miles, no issues. Only pumped up to max when towing my TT.

 

[bullwinkle]

This is what I do. If towing i'll probably do 5 under max due to heat expansion.

Expansion is unreal under load & at highway speeds-the Transit dash indicated PSI goes from 85 cold to over 100!

 

[wwillson]

Expansion is unreal under load & at highway speeds-the Transit dash indicated PSI goes from 85 cold to over 100!

Yes, I see pressure increases like this almost every time to tow the 5th wheel. The tires are made to handle the expansion. Said a different way, the tire engineers expect pressure increases during operation and design the tire load carrying capacity with the expansion, so if you try to outsmart the engineers by lowering your cold pressure so that at operating temperature the tires don't exceed max sidewall pressure, all you have done is lowered your tire carrying capacity. You have done nothing to 'save' your tires from over inflation, because they are supposed to be 'over inflated' at operating temperature.