What Back Spacing and Offset do I need?

i have stock 17 inch rims with 265x70x17 tires. After installing the leveling kit and 2 inch wheel spacers, which really made the truck ride and handle great, I have about an inch of tire riding outside the fenders. I would like to run a taller narrower tire, and need to know what specs, backspacing and offset, I need to have in a 17 or 18/inch rim, to get the tires back inside the fenders and and closer to the suspension, since I have a lot of room there now.
Can anyone who is proficient at these calculations help out. I just want to know what to look for when I purchase new rims, and not get shammed by some eager tire and wheel salesman.

 

The easiest thing to do would be to take off the spacers. That obviously would move things back inside the fenders. Other than that, you need a wheel with a positive offset that is greater than what your stock wheels are. I don’t know the specs of your wheels for offset, but let’s say for example it is +20. You would need somewhere around +45 offset to move your wheel in 1 inch. Not impossible, but hard to find. Better option would be to pull off the 2” spacers and then find a wheel somewhere around 0 or +10 offset. For every 25.4mm difference in offset, your wheel moves in or out 1”. Positive offset moves it in, negative moves it out.

Backspacing comes into play when you are looking at rim width changes. IMO - backspacing is less important unless you’re doing something drastic like changing from a 7” wide rim to a 9.5”+ wide rim. Offset is easier to calculate inward/outward movement in your wheel well IMO.

 

Thank you
Your explanation makes sense of the whole offset/ backspacing issue.
I will probably take your advice and just remove the spacers. The lift was minimal and don’t believe the ride will be affected at all.

 

revivalOL Thanks for the explanation regarding Pos/Neg offset, i'm sure this will come in handy for a lot of peeps who stumbles upon this thread.
I know it helped me to better to understand, Bravo.