Tires: P Rated to LT C Rated PSI, tire placard, stock tires

Question
Barry,

I have a 06 Off Road Xterra and switched the stock tires 265/75/R16 P rated BGF Rugged Trails with an LT 265/75/R16 C rated Bridgestone Revos.  I am unsure on the tire pressure adjustment.  The P rated ran at the manufacturer's recommended 35 PSI  and I have been running the C Rated tires at 35 PSI for the last 20k.  I read your not a fan of the switch and actually didn't realize it when they were installed.  I recently read I am probably causing excess heat and tread wear if you inflate a C rated tire at the same as a P rated.

Any help on a the correct psi would be greatly appreciated.  I saw you figured around 48 psi for a D rated, but couldn't figure out how you did it or a conversion between different loads.

Thanks so much!

Answer
Aric,

I will say it again, I am not a fan of switching from P metric tires to LT metric tires - and in a moment you will see why.

According to Tire Guides, your vehicle tire placard should say the original tire size was P265/75R16 inflated to 35 psi.  So that info is correct.

In order to carry the same load as a P265/75r16 does at 35 psi, an LT265/75R16 needs to use 48 psi - a 13 psi increase, and that is why I am not a fan of these swaps.

Just and FYI, the load carrying capacity of a C Load Range, and a D Load Range are the same at the same inflation, it's just that the Load Range D can use higher inflation pressures.  The same would apply to Load Range E.