IROK size question

[SHoppe715]

I'm doing more web-wheeling and future scheming for the GB. I don't want a bigger diameter tire because of the gearing I've got and I want to mount the spare under the bed without it hanging down too far. A HMMWV tire will work well for the spare, but I want a wider / softer footprint.

So I was comparing the 36/13.50-16.5 and the 37/14.00-16.5 bias ply IROK and it seems the 36" is bigger in all dimensions except weight, price, and approved rim width. It's supposedly about 1/2" taller with 1 1/2" wider tread, but mounts on a narrower rim (my rims are 9.75" wide), is 13lb lighter, and cost $10 less per tire. Am I reading this stuff right?

http://www.4wheelparts.com/Tires/IROK-Bi...&t_pl=3866

http://store.summitracing.com/egnsearch....wordSearch