Tires: tire pressure, cooper discoverer stt, tire placard

Question
Hi,
Just got a 2006 Nissan frontier with aftermarket rims and tires.  The truck is leveled.  The tires are Cooper STT 275/65/18 and I want to find out the best tire pressure for daily driving (in town and highway mixed)  Thank you and have a great day!

Answer
Ron,

On every vehicle sold in the US - and I understand this is a worldwide practice as well - 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.

According to Tire Guides, a publication that summarizes vehicle tires placards, a 2008 Nissan Frontier came with a variety of tire sizes:  P265/75R16, P265/70R16, P265/65R17, and P235/75R16 - all inflated to 35 psi.

BUT

A Cooper Discoverer STT comes in  an LT275/65R18.  Those little letters "LT" are important because LT tires are constructed different than "P" type tires.

In order to carry the same load, an LT275/65R18 needs to use 47 psi - which is why I do not recommend replacing "P" type tires with "LT" type tires.