Can anyone help a fellow Zuker out? I am in the process of doing a Yota axle swap, and do not know what size of wheel would be best. I am going to run 35 x 12.50 R15 tires. I know I need 6x5.5 bolt pattern but what back spacing do I need and should I use a 15x8 wheel or a 15x10. Thanks for any help

15/8 I like the least amount of back spacing (2") it really depends on the terain your running how tall your rig is etc. What brand tire you gonna run?

I'm going to be running Maxxis Trepador Radials. I run around on a variety of terrain(rocks,hills, and mud)

15x8 is the way to go, you need some bulge on the sidewall. if you go too wide, you'll look like the lowriders stickings their tires too far out with a wide rim instead of just getting a tire made for the wider rim.
the backspacing is pretty standard, if you space it back in then it may rub stuff underneath. standard backspacing is about 3-4", that's all you need.
even on 15x14 rims, the backspacing is still the same. all the width is added to the outside of the tire, cuz if it went inward, it would rub everything. Now, if you got wider axles then you may have the room to run extra backspacing, but why go modify or buy rims like that when stockers will do you? Most axles are made for stock offsets. a 12.50 isn't too wide to cause a problem.
jd

Personally, I would go with 15x8 alum rims. They are so much lighter which reduces vehicle weight and saves on fuel.

It makes them easier to change and they do not rust. They are easier for your engine to turn and they look better.

I can tell the difference when driving on the highway.

Thanks for the advice. The 15x8 seem to be the way to go. I wasn't sure if it was to norrow for a 12.5 wide tire.