Tires: Aftermarket wheels and tires, aftermarket wheels and tires, wheels and tires

Question
Barry-

I have a 2004 2500 Ram 4x4.  The placard on the truck for the front lists LT265/70 R17-E 17x7.5 rim at 60 PSI and for the rear LT265/70 R17-E 17.7.5 rim at 70 PSI.  I want to put on a new set of wheels and tires.  I am looking at a 17x8.5 wheels with a 6" backspacing, 32mm offset.  The tires are 35x12.50R17LT with a max load of 3640 at 65 PSI load E rating.  I have two questions about the wheels.  Is there any risk going with the wider rim?  Also, I was told the 6" backspacing and 32mm offset are a Dodge specification.  Do you know what the proper backspacing and offset should be with the wider rim?  And for the tires, what PSI should I run them at unloaded and loaded?  Thanks in advance.  I have learned so much about tires reading the answers to your previous questions.

Answer
Eric,

To get the same load carrying capacity as the tires currently on your vehicle:  LT265/70R17 at 60 psi front anf 70 psi rear - a 32 X 12.50R17 LT would need 43 psi front and 51 psi rear.

But that's the only question I can answer of the ones you asked.  here's why:

Backspacing;  This is a vehicle fitment issue and I don't have access to those types of charts - I'm strictly a tire guy - only the rubber part.

Load / Unloaded Pressure:  Long story - short answer.  If the vehicle manufacturer publishes an unloaded tire inflation pressure recommendation, I can deal with that, but they rarely do, and without that I won't have enough information to do a calculation.