BFGs tend to be the smallest in any stated diameter, in my experience. I've also measured Procomp 37s at just a tiny hair under 37. However they are not DOT tires and wear fast on pavement. The Goodyear MT/Rs on my JK were 34.8 for a 35, while the BFGs were much closer to 34. Mostly nobody gives you the full size, like a 55" TV is only 54.1, rounded up in marketing numbers.