TIRE PRESSURE CONFUSION

[adrian del valle]

I weighed my 2018 Ram 2500 diesel crew cab on a cat scale empty and the front axle was a lot heavier than the rear. I had nothing in the truck except for a full tank of gas, my skinny wife (130 lbs.) and our dachshund (18 lbs.).
Even if both front and rear were the same weight, shouldn't the air pressure in the tires be the same 80 Lbs., and not the recommended 60 in front and 80 in the rear?

 

[Timd32]

You could find 80 is pretty rough ride and alot of us lower that down quite a bit when not hauling.

I think I'm frt 60/ rear 45, maybe 55 in the rear forget off hand.

Will see where some others chime in at.

 

[BigPapa]

I run 65 front and 50 rear when empty. When I tow heavy I go 80/80.

 

[AH64ID]

The axle weight ratings are different, thou 60/80 is more pressure than is needed for the AWR's on a 2500.

60 is good for 6,040lbs and 80 is good for 7,280lbs.

I adjust my tire pressure based on what the truck weighs. Right now it's at 55/35, but there aren't any alarms on a 3500.

 

[Blackbrush]

60F/50R unloaded

 

[lpennock]

The door jam pressure are the pressures for a maximum loaded truck. The front weight doesn't change much between loaded and unload but the rear of course does. Unloaded the rear pressure is much more than required.

Now for the bad news. TPMS on a 2500 alerts if the tire pressure is 10% (could be 5% or 20% I'm working from memory) below the door jamb pressure. So unless you change the tpms settings you can't drop the rear that much before getting a light on the dash.

Before you ask, the dealer cannot change the TPMS thresholds. FCA removed that ability from there tools. Now for the good news. You can get AlfaOBD and change the pressures yourself to something more reasonable like 40psi rear. Actual pressure you want is based on tire size and the actual weight you got when you weighed.

 

[HPSimpson]

When not towing I run all tires 60psi, loaded 80 all tires.

 

[EZeis]

60/80 on my 18 3500 SRW. Run it all the time. Grew tried of lowering and refilling the rear tires. The rear air suspension makes it ride well even at 80 psi empty in the rears.

Earl

 

[josephc1]

60/40 empty, 60/60 towing. Changed TPMS years ago to 30 all around.

 

[SSchang]

I run 70 front, 70 rear when truck is empty. When I load the camper, 70 front, 105 rear. Of course they are 19.5" load range G tire. When I put the factory tires & wheels on for winter, 65 front and 50 rear.

Scott

 

[kthaxton]

65/40 empty here, usually around 65/60 towing (I have slightly larger tires than stock)
As silly as it sounds, your truck cannot carry enough weight to necessitate 80 psi in the rear.

 

[SnoKing]

I run 60 all the time in the front tires. I do not know how one would overload the front axle and require 80 PSI inflation. I ran 80 PSI in the rear tires towing the 5th wheel and 65 with the TT. Empty I run the rears at 45 PSI. At 45 PSI they are rated to 2470 or 4940 for the axle. At 4940 one has over 1500 pounds of reserve before unloading. So small loads from the lumber store are not an issue. Everytime Costco rotates my tires, I have to de-air the rears before leaving their parking lot. There is a notice difference in ride and some difference in handling with 80 in the rear tires. 80 in the rears with rain on the roadway would not be so good.

 

[Cummins12V98]

It’s amazing to see how many over inflate the rears and under inflate the fronts.

 

[AH64ID]

It’s amazing to see how many over inflate the rears and under inflate the fronts.

I don’t see anyone in here under inflating their fronts.

Many do run more pressure than needed thou, front and rear.

 

[SnoKing]

Duallies and SRW are different animals.

 

[AKDoug]

I'm not going back and forth on pressures or I'd be doing it all day. I used to run 80psi all the way around, but found 70 to be sufficient.

 

[Cummins12V98]

I don’t see anyone in here under inflating their fronts.

Many do run more pressure than needed thou, front and rear.

It was more of a general statement.

 

[SnoKing]

I don’t see anyone in here under inflating their fronts.

Many do run more pressure than needed thou, front and rear.

Anyone not running 80 PSI in the fronts of a dualie is probably not doing themselves a favor.

 

[lpennock]

Anyone not running 80 PSI in the fronts of a dualie is probably not doing themselves a favor.

I actually looked at the load tables after weighting my 18. Only 75 is needed for my unloaded weight but 80 is required to make the Door Jam rating. I do run 80 so I don't have to worry about temperature changes as much. Bottom line, 75-80 is fine most of the time.

 

[Cummins12V98]

I actually looked at the load tables after weighting my 18. Only 75 is needed for my unloaded weight but 80 is required to make the Door Jam rating. I do run 80 so I don't have to worry about temperature changes as much. Bottom line, 75-80 is fine most of the time.

Run 75 and report back. You will be wearing the edges. I wish I could run over 80psi with my front axle running almost 5,500#

IMHO they need a higher rated tire specifically for the front axle.

Anyone have thoughts on running 85psi fronts???