Tires: tir pressure, tire placard, tire guides

Question
I just bought 4 uniroyal 31.10.50 from Walmart they put 30psi in them the sidewall read 50psi. Whats the correct pressure?( 1997 nissan4x4 kincab)

Answer
Dwayne,

On every vehicle sold in the US, there is a tire placard that lists the original tire size and the proper pressure for that size.  It is usually located on a doorpost or in the glovebox, but it might alos be on the fuel filler door or in the trunk.  Please check this as what I am about to write depends on this being correct.

According to Tire Guides, there were several different version of your truck and they came with different tire sizes - but one of the versions came with 31X10.50R15LT's inflated to 26 psi front and rear.