Tire manufacturers state on their website what the recommended rim width is for each tire they make. While a 7" rim may be ok for (example) Toyo A/T they might recommend a minimum 8" rim for their M/T tire. Look up the exact tire you want to run to confirm they are ok for that specific tire.
Rim width is more important when you air down. Too narrow and the bead will want to pop off a skinny rim. Also any warentee issues on a mission matched tire/rim combo could void the tire warentee and leave you holding the bag.
These are the rims I got 15x7. I want to fit 32x11.5R15 tires to them. All rims are in top shape. I got a set of 5 of them which are hard to find here. Forgot to mention aI have a 2 inhc lift kit PLUS 40mm coil spacers... I plan on removing the coil spacers
They will work without wheel spacers, but the rear spring clearance is limited. If you are driving on road only, you're good. I bought a 99' Sahara with 33x12.50 tires on stock wheels and it was fine (to my shock) on the street. Adjusting the steering stops up front was still a huge issue. It had NO LIFT too. I got a good deal for $6,000 and sold it for a nice profit.
You are fine...
People run 15x8's with 12.50's and have for many 's
Why is that?
wwwwweeeeellllll.....
11 50 just became available not that long ago. There weren't hardly any 11.50 even offered thus the norm became 12.50 as the modified tire of choice. 7 or less is a bit much to seat a 12.50 so new rims of 8" or 10" became the norm.
The issue with the FACTORY wheels is they have too much backspacing for an 11.5" wide tire. In other words the tires would rub. Factory backspacing is from 5.25" to 5.5" which is too much for that wide of a tire. Even 31x10.50 tires rub a tad up front with the factory wheels which is why there's a need to add a washer or two to to each of the steering stop bolts to prevent 31x10.50 tires from rubbing on the control arms.
Here is an example of 32” BFG KOs on factory Rims. They definitely rub at full lock in the front on level ground. This was my daily driver so never offloaded it.