Quote Originally Posted by JHarris1385
So essentially if I was and I am wanting to get a 16'' rim, what would be the exact or possible dimensions???
The stock wheels for Isuzu are 15", 16", and 18", 7J (rim width), 6x5.5, ET+38 (offset), back spacing (5.5), D100 (center bore).
I believe for the 245/75 the best would be 7J, ET+25 through ET+38 or 7.5J ET+20 through ET+32. See picture to convert ET to backspacing:

Normally, if you go with wider tires you should end with wider rims and lower offset (f.e. for 265 tires it would be best 7.5J or 8J and ET=38-(265-245)/2=28).
The center bore should be not less, but common 108-110 are OK (you hardly find 100 exactly, but beware of the wheels with D78 - they will not fit!).

I'm personally running 245/70R16 on 7J ET+20 and I wish the bigger offset since my car become dirty a bit quickly.