The pressure marked on the tire is amount needed to get the maximum load bearing, not the normal operating pressure.
The tires on your pickup may say they are rated for 1874 lbs of load at 45 lbs pressure, but the recommended operating pressure is 30 lbs.
Are you sure about the 30 psi? I remember inflating my pickup and car tires to 30-32 psi and
it was rated on the tire. GMC recommends tire inflation on my 2008 2500HD Duramax pickup at 60 front and 70 rear and the tires are rated at 75 psi. Once again it is rated on the tire.
I am changing the rims over to 20 inch 6 bolt stud centered Budd rims with lock rings and agree that operating with under-inflated tires can lead to premature tire failure.
