Tires: 1994 Chevy Suburban K1500 Tire Pressure, tire placard, rim width

Question
I recently bought a 1994 Suburban K1500 Silverado (4x4 Wagon) with LT265/75R16 Load D tire size. What is the ideal tire pressure? My tire certification card is mostly faded out so I am unable to read it. However I was able to determine that the tire size that came with the car was LT245/75R16 Load C. Thanks for your help!

Answer
Matt,

If what you've derived from the vehicle tire placard is correct, then the original pressure should read 45 psi front and rear.  I got this from a book that summarizes vehicle tire placards, called Tire Guides.  Check to see if this might be what it says as what I am about to write depends on this being correct.

If that is so, then in order to carry the same load, an LT265/75R16 needs to use 39 psi.

But there is another problem.  According to Tire Guides the stock rim width is 6 1/2" - and the minimum rim width for an LT265/75R16 is 7".  Using a rim width the is too narrow tends to make the tread arch across the tread face, and that leads to excessive wear in the center of the tread, as well as a sensitivity to following the grooves and ruts in the highway and a certain sensitivity to wind.  There's nothing you can do about that except to return to a properly sized tire.