Unloaded tow vehicle tire pressures

[RoccoJohn]

I just purchased a Ford 250 diesel to pull my AS. The tire markings call for a max pressure of 80 psi, and the door label calls for 65 psi in the front tires and 80 psi in the rear. I never carry a load except when towing - otherwise it's just my wife and I and the truck.
Should I drop the pressure in the rear to match the front for a better ride when empty, or even go below the recommended 65 psi for all of the tires?

[ROBERT CROSS]

Just what i do....

Recommended max pressures on our Mich LTX.. 80psi

After some trial's.... Front 65 rear 60... unloaded. cold

Towing....75 F & R. cold


Bob

[overlander63]

Originally Posted by GaRoc

I just purchased a Ford 250 diesel to pull my AS. The tire markings call for a max pressure of 80 psi, and the door label calls for 65 psi in the front tires and 80 psi in the rear. I never carry a load except when towing - otherwise it's just my wife and I and the truck.
Should I drop the pressure in the rear to match the front for a better ride when empty, or even go below the recommended 65 psi for all of the tires?

I've had problems with the different pressures. When rotating tires, the rear tires will then have to be inflated to 80, and the fronts will have to be deflated to 65. Along with the chances of having the wrong pressures in the tires, I've had issues with the belts in the tires separating, ostensibly from changing the pressures repeatedly. It's better to have all the same pressure front and back.
Whether 80, 65, or something else, would have to be up to the individual owner. I wouldn't lower the pressure below 65, or the maximum over 80, though.

[GO Bob]

The owners manual should have it. If not the tire manufacturer will and you will have to weight the axles.

DO NOT forget to reinflate

[r carl]

Originally Posted by ROBERT CROSS

Just what i do....

Recommended max pressures on our Mich LTX.. 80psi

After some trial's.... Front 65 rear 60... unloaded. cold

Towing....75 F & R. cold


Bob

Same here.

[Alumaholic]

After much too much research I learned it is okay to adjust your tire inflation to match the load. Michelin once published a chart to help you maintain proper inflation for different loads. I printed it on a business card and kept it in my wallet until I learned the following.

With you tires at maximum recommended inflation and under a full load, try slipping a credit card under the tires (on a smooth concrete parking ramp).

Then try the same thing with max inflation and no load. You will find the credit card slips under the edge of the tire. Remove air until you have equal tire and surface contact across the width of your tread. When you check the inflation with a tire pressure guage you will find that Bob and R Carl are correct.

[CanoeStream]

There is some guidance on varying pressures to suit the load. Past useful posts are here and here. You might want to read up and down that thread for more of the context.

A useful link from Marathon - http://www.tirerack.com/images/tires...plications.pdf

[RoccoJohn]

The credit card suggestion sounds reasonable - even pressure across the treads makes sense. Thanks.