Tires: tire pressure, psi max, tire wall

Question
Hi Mr Smith, I  just recently install a set of nitto terra grapplers LT325/60R18 119S, the tire shop put 30 psi in it and the tire wall call for 50 psi max, I like to know if I need to add air. thank you Sr.

Answer
Ciro,

On every vehicle sold in the US, there is a sticker - commonly called the placard - that will list the original tire size and the proper pressure for that size.

But you do not have the original tire size, so that means we have to recalculate the pressure, trying to match the original load carrying capacity.  So we need to know what the vehicle placard says - including the letters that may be attached in front of or following the size listed.

There are some books available that will list this information by year, make, and model, but I know that you have a vehicle that probably has several possible tire size and several possible pressure listed on the placard, so I will need to know what the placard says.