the more i read and do research, the more i get confused

i mean you can mount(ok, not that you can but i´ve seen here a lot of rigs with that set up) a 35x12.50(13.39in width) nitto mud grappler tire on a sahara stock wheel, but you can not mount a 35x14.50(12.80in width) irok tire on the stock sahara wheel... how come, since the mud grapplers are wider... or you can mount a 33x12.50(12.7in width) toyo open country m/t tire but you can not mount a 33x13.5(12.8in width) irok tire on a sahara wheel!!!!

i`ve seen pics of nitto trail grapplers 35x12.50(13.39in width) mounted on stock sahara wheels!!!!

i wanna get super swamper irok radials on my stock saharas so bad i have 1,5" spacers and all the goodies ready!!!

i´m going nuts about this matter please help!!!

 

Because its about a combination of tire construction and interference by lawyers, and not just about section width.

Different tire's of the same size can spec wildly different minimum rim sizes.

Tire sizes are nominal...and there is a great deal of variability.

The other issue, is that for street use (Where the accidents happen and the lawyers come into play...) you normally use a wider rim/less sidewall bulge than for offroad.

Off road, people are happily humming along on 12.5"-13.5" tires on 7"-8" rims, etc....even though the tire SPEC's might say a wider minimum rim is required.

So, take the minimum recommended rim widths with a grain of salt...but, keep in mind that for some tires, you have more or less leeway than with others....and that generally, the narrower rims work better OFF road, and the wider rims work better ON the road.

I have 305/70/16's on 7" rims, and I have 33 x 13.5/16 on 7" rims, and both work great, with even tire wear, no problems.

The 33 x 13.5's are Super Swamper LTB's, and they SPEC a minimum of a 9" rim width, its even molded into the tire's sidewall.

The 305/70's spec a minimum rim width of 8"

 

I think your confusing is around two separate issues.

One is range of rim widths you can safely mount a tire. Most 12.5" wide tires specify at least a 8.0-8.5" wide rim. However many of us are using these tires on the stock rim which is only 7.5". The manufacturers include a safety margin in their specs for legal reasons, so in most cases this is still within the proper rim width.

I watched carefully when my KM2S were mounted and inspected them afterwards and there is not any excessive bulging and they don't run hot on highway. I think I could probably get away with 13.5" wide KM2s (from a rim width perspective), but these tires are a bit on the narrow side. For instance I would not consider mounting a 13.5 MTZ on these rims.


The second issue is tire clearance within the fenderwell. If you have enough lift or or trim enough parts you can fit a wider and taller tire. The 1.5" Spidertrax spacers provide enough clearance for the 12.5" wide tires on the stock wheels. A 13.5" wide tire might clear but there might be some rub. IMO 14.5" are out of the question from both perspectives.

 

I've run bias ply 14.50's on an 8in rim, no probs, aired down to 5lbs in sand. But hell, I only ran 15-20 on road on my cj-5