My car takes 15580R13 tires. Will I get better gas millage if I use 165 or 185 cirferance tires?

I was told that the first number set like 155,165,185 is the cirference of the tire. The larger the number the larger the dia. But as the diameter of the tire increases so does it's width which would increase friction. So will I get better millage from a larger dia. (185) tire that is a little bit wider of from a smaller narrower tire (155)