I was hoping I could get some guidance on wheel tire combo.

I have a 2" RC level and the wheels I want come in a 0 or +18mm offset on 20" wheel. I would also like to run either a 285/65/20 BFG K02 or a 275/65/20 Toyo Open Country ATIII. Which combination would work best without rubbing the crash bars? I don't mine a little plastic trimming.

 

No offset or +18 is dramatically different based on the width of wheel.

You could be happy with 0 on a 9" wheel and unhappy with 0 on a 10" wheel.

Pick the size wheel first, then ask the question.

 

My bad. Looking at a 20x9. Talked to a tech at Stage 3 and he thinks either offset with a 285/65/20 would be fine. He stated anything 11.5" wide or narrower would be ok.

 

My best guess is you will be fine with the 275/65/20 with no rubbing on either offset.

The 285/65/20 - I just read a post where a member has these tires and he said:

I run 285/65R20 tires on a 2.25" level on stock wheels and no spacers. The tires measure to 34.6"x11.5" and do not rub in any direction and motion. If I were to add a 1.25" spacer to the wheels or run an aftermarket wheel with +20mm offset I would rub severely on the crash bars and wheel liner.