Forum Discussion

Barkoff's avatar
Barkoff
Explorer
Mar 14, 2015

Opinions on PSI

So I decided to go with to go with the Vision 7.5 Heavy Hauler and the Hercules 19.5 265's all around, so what would you advise running them at?

They are rated to 123 psi max, but I'm pretty sure I don't need that much in the tires.

After having them mounted I took them up to the truck stop about 12 miles away, they sure felt a lot better than the 16" 265 E rated rubber I had on there before. The same railroad tracks I used to bounce up and down three times on, I now just bounced one time, they felt firm with 100 psi in the rear, and 90 in the front. Took them up to 70mph (rarely go faster than that) and they were balanced well, no vibration at all.

When I arrived at the truck stop, I took some weights, the front axle of the Dodge Ram weighed in at 4440 lbs, the rear axle 6220 lbs, and the overall weight of the Ram and Lance 950 was 10,660 lbs, with empty water tanks and no groceries or luggage in the camper.

The 6260 lbs in the rear, with a dry, empty camper, the possibilities of towing a boat, confirmed I was up against the limits of my old 16" 265's E rated. Being a single axle 2500, the camper still gets some slow speed rocking, but feels a lot more firm.

Does 100 in the rear, 90 in the front, pretty much match what others are running at?

Thank you.


  • I run my 225's at 75 front and 90 or 95 rear. My rig is a little over 12000 lbs wet. I find all my weight is on the rear tires with the crew cab.

    Paul
  • I run 85 front 95 rear...but haven't done a lot of trial and error.
  • Mich F wrote:
    Try Michelin's Load and Inflation Table They probably make your size tire, should be the same specs for weight,


    Thanks, that helped.

    Looks like I could run them down a bit, but of course Hercules is no Michelin, so I think I'll add about 10psi to those figures, so 85-90 on the front, 95-100 on the rears sounds right with the camper on.
  • On my SRW with 19.5s, I ran 80-90 front and 95-105 rear. The front tended to wander more with higher pressure. I could have had more air in the rear, but at 100 I was 20 lbs over the stock tires which seemed plenty.

    Fwiw, my F450 which is a DRW has air pressure ratings of 80 front and 75 rear for the 19.5s to reach the 14,500 GVWR.
  • I am heavier and running 245s but 85/100 with just the camper on, towing my 3 horse slant load with two horses I run 90/110 and love it
  • I'd go to the OEM website and find the PSI/Load table (most have one) or find the (different manufacturers call it different things) "maximum sag rating" or some such.

    The 1st document will have a list of weights and recommended PSI's to run the tires at. The 2nd outlines how distorted or out of round your tires can be (or how much axle sag) is allowed or recommended.