When I bought my Dodge 190P, the seller told me to run 80 lbs of air pressure in the rear tires. I thought this would be excessive, but I've also read others saying the same thing. Makes no sense to me. I'd prefer 60 lbs. Why 80???

 

Likely 80 lbs is what the tires want to carry max load. If you aren't carrying that much weight, you could dial it down a bit for a slightly more cushy ride.

 

My F-350 has tires with a MAXIMUM pressure of 90 psi. I generally run 45 psi. This gives a better ride and handling. The higher pressure is to keep the tires from squatting down and destroying the side walls. Running empty you run the risk of wearing the center of the tread out prematurely. This will also reduce your contact patch and give less grip.

 

Also have to be aware of the maximum pressure the rims can handle. I'm pretty sure steel factory rims max out at 65 PSI with rubber valve stems, or 80 PSI only if using reinforced valve stems, not rubber ones. Sometimes there is a Max. PSI rating stamped on the rim somewhere.