Metric Section width Height Flotation.

15"
215/75/15 8.46 27.69 28x8.5x15
235/75/15 9.25 28.88 29x9.5x15
245/75/15 9.65 29.47 30x10x15
265/75/15 10.43 30.64 31x10.5x15
325/60/15 12.79 30.35 31x13x15

16"
235/70/16 9.25 28.9 29x9.5x16
245/70/16 9.65 29.5 30x10x16
255/70/16 10.04 30.05 31x10.5x16
275/70/16 10.83 31.16 32x11x16
305/70/16 12.00 32.80 33x12.5x16
325/70/16 12.79 33.90 34x13x16
225/75/16 8.86 29.29 30x9x16
245/75/16 9.65 30.48 31x10x16
265/75/16 10.43 31.64 32x10.5x16
285/75/16 11.22 32.83 33x11.5x16
295/75/16 11.61 33.42 34x12x16
315/75/16 12.40 34.6 35x12.5x16
265/80/16 10.43 32.69 33x10.5x16
325/80/16 12.79 36.46 37x13x16
235/85/16 9.25 31.73 32x9.5x16
255/85/16 10.04 33.07 34x10.5x16
305/85/16 12.00 36.40 37x12.5x16
365/65/16 14.37 34.68 35x14.5x16

17"

265/70/17 10.43 31.6 32x10.5x17
285/70/17 11.22 32.7 33x11.5x17

18"
285/60/18 11.22 31.46 32x11.5x18
325/60/18 12.79 33.34 34x13x18
325/65/18 12.79 34.62 35x13x18
355/65/18 13.97 36.16 37x14.5x18

Feel free to add some to this chart.
I know there are some odd ball sizes, most of them are used by BF Goodrich, Nitto/Toyo, and
Buckshot.