I've run 265/65r18s on stock suspension without rubbing. Some people report minor rubbing. That's the same size as 265/75r16s pretty much.

If you want no risk of rubbing, go for 265/60r18s or 265/70r16s. Personally I'd go for the next size up (listed above) though.

Also, any reason you want BFGs in particular? You can get Fallen Wildpeak AT3Ws for a lot cheaper, and I personally like them better. I have two sets (on separate vehicles) right now. I expect to get 45-50k out of both sets, they're more quiet than the BFGs, and I've yet to get stuck on them. Great road manners, too. I can't speak highly enough of them.

 

Keep in mind with the 265/75R16 you’ll be going 3-5 mph over your speedometer’s speed. I’ve noticed this on my Disco.

 

I prefer the Cooper Discovery Maxx myself, BF Goodrich are not as nice on wet roads.

 

 

BFG makes stock size 18" KO2, if you have 18's you can do the stock size

 

I'm running the Falken 265/75/16 .I've had many different style tires on multiple vehicles and honestly, I believe these are the best tires I've ever had. They wear perfectly, they do AMAZING on wet roads (no jerk in the wheel or hydroplaning), 8.5/10 on snow and ice and haven't had them on the trails so can't give any rating .

 

My vote goes to Goodyear Duratracs. Great tires.

 

 

If you're going to be doing any off roading then I'd recommend going up in size. Especially since you've got 18' rims.