Tires: Proper Tire Pressure, jeep cherokee sport, tire placard

Question
What is the operating air pressure for 30x9.50R15 104s tire on a 2000 jeep Cherokee sport 4.0 liter V6 4x4? These are not the stock tires and a friend of mine who is a mechanic told me to run them at 50 PSI and to me that just doesn't seem right to run them at max pressure.

Answer
Steve,

On every vehicle sold in the US - and I understand this is a worldwide practice as well - there is a sticker – commonly called the vehicle 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 tire placards, a 200 Jeep Cherokee Sport 4X4 originally came with P225/75R15's on 7" wide rims, inflated to 33 psi front and rear.

You should check your vehicle tire placard to see if that is what it says - because what follows is based on that information and if it is different, then what is below is wrong.

But assuming that info matches that placard, then in order to carry the same load as a P225/75R15 does at 33 psi, a 30X9.50R15LT needs to use 38 psi.