Figuring out wheel offset & backspacing

Hi everyone, this is my first time here and hope someone could help me figure this out.
I have a 2000 Tacoma SR5 with a 3" suspension lift and 1" body lift. I currently have 31"tires (31x10.5r15)
I am upgrading both my tires and rims and need to figure out the offset and/or backspacing for the new rims. I found many sites on how to calculate this but I am having a hard time wrapping my head around it.
The new tires I am getting are 285/75R15, this is about a 33" tire and width is about 11.25", so a bit taller and wider then my current tires.
My current rims have a 19mm positive offset, (about 3/4" positive offset, 4&3/4" backspace. 8"wide rim). I currently have 1" of clearance from the tire to any parts, with lots of space (height) in wheel well. So the bigger diameter isn't an issue.
So, what offset or backspace would you recommend to maintain my 1"clearance?
Thanks!!

 

I have 285/75/16 and about 2-2.5"lift. My wheels had 5.25" of backspacing. So I had to get a 1.25" spacer to clear the uca's. I think whatever wheel you go with you want at least 4" of backspacing to keep you clear. After the spacer it brought my spacing to 4". I now have about 3/4 -1" of clearance.

 

A zero offset/4" back spacing is what I was thinking.
Thanks!!

 

All assuming a 16x8 wheel:
-4.5" of BS will rub the frame
-4" of BS will rub the pinch weld
You can cut the pinch weld, can't do much about the frame...I'd recommend (and currently do) running a wheel with 4" of backspacing.

Also, 4.5" of BS = 0 offset, 4" of BS = -12mm offset.

 

Hmm, more to think about.. I tried a good wheel calculator online, punched in my old wheel dimensions and the new ones,according to that a 10mm positive offset would not rub.
This is why I am so confused, with my own calculations and others I still very from a 10mm positive offset to a 12 mm negative offset. It seems like more and more I won't know the right answer till I put them on. But once the tire is on the rim I own it.
Thanks for your answers, still need help though..

 

In your original post you say you are buying a 286/75/15 tire, I'm assuming this is a typo and you are getting a 285/75/16.

An 8" wide wheel with +10mm offset is going to rub on the frame when turning.

If you run a mild AT tire you can probably get away with running a wheel with 4.5" of backspacing and only have minor rub on the frame. However, since you already have a body lift (this will mitigate some of the pinch weld rubbing) I would run a wheel with 4" of backspacing and call it a day.

Here is my experience (my truck has a 3" OME lift):
-285/75/16 Hankook Dynapro MT tires w/ 16x8 4.5" BS, (0 offset): rubbed the frame badly on sharp turns
-285/75/16 Hankook Dynapro MT tires w/ 16x8 4" BS (-12 offset): rubbed pinch weld, but after trimming its mostly gone.

Hope this helps.

 

I just got new wheels and tires, 16x8 wheelsMK6s, 265/70/16 tires. wheels have 4.5 backspace, -10 offset, no rubbing anywhere, stick out from flares about1.5", no lift ,stock.

 

How where you not rubbing your uca's with 4.5" backspacing and 285/75's??

 

Always had a finger width gap between the tire and UCA. Never heard of people having an issue with aftermarket wheels and rubbing. I know with the stock wheels you will rub the UCA.

 

Thanks, Ya I would suspect though with any suspension flex you would be rubbing the uca pretty good. Still learning more about this stuff myself, so I was just curious.

 

Don't quote me on this but I'm pretty sure that the UCA and wheel move in unison with each other, regardless of suspension articulation. In essence you could only have .25" gap between the tire and UCA and you would never rub. If it doesn't touch when the truck is stationary you'll never rub when the truck is in motion.