Tires: tire pressure, tire placard, mitsubishi montero

Question
What is the correct tire pressure for Uniroyal Liberator A/T
31/10.5 R15 LT  on a 1991 Mitsubishi Montero 4x4?

Answer
Carlos,

On every vehicle sold in the US, there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size.  The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.

BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.

The placard becomes the starting point for any calculation involving a change in tire size, so it is important that you check to make sure what I am about to write is correct.

According to Tire Guides a 1991 Mitsubishi Montero 4X4 originally came with P235/75R15's inflated to 26 psi front / 35 psi rear.  

If this information is correct, in order to carry the same loas as a P235/75R15 does at 26 / 35 a 31x10.50R15LT needs to use 31 psi / 38 psi.