METRIC TIRE SIZE CONVERSION CHART

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15 inch tires sizes

Width Aspect Wheel Diameter Section Width
205 70 15 26.3 8.1
245 70 15 28.5 9.6
205 75 15 27.1 8.1
215 75 15 27.7 8.5
225 75 15 28.3 8.9
235 75 15 28.9 9.3
245 75 15 29.5 9.6
265 75 15 30.6 10.4
215 85 15 29.4 8.5
245 85 15 31.4 9.6
275 85 15 33.4 10.8
315 85 15 36.1 12.4
325 60 15 30.4 12.8


 

16 inch tires sizes

Width Aspect Wheel Diameter Section Width
305 65 16 31.6 12.0
345 65 16 33.7 13.6
245 70 16 29.5 9.6
305 70 16 32.8 12.0
225 75 16 29.3 8.9
245 75 16 30.5 9.6
265 75 16 31.6 10.4
285 75 16 32.8 11.2
295 75 16 33.3 11.6
215 85 16 30.4 8.5
235 85 16 31.7 9.3
255 85 16 33.1 10.0
265 85 16 33.7 10.4
305 85 16 36.4 12.0
255 70 16 30.1 10.0


The above numbers are computed values and some rounding has been done on the computed values. The actual tire sizes can and will vary depending on the tire manufacturer.

To compute the values in the table above, use the formula of:

HEIGHT = ((width * aspect-ratio * 2) / 2550) + rim size

WIDTH = (width / 25.50 )

For example, a 235/75R15 tire is ((235*75*2)/2550)+15) = 28.8 inches of tire height. The tire width is figured by 235/25.5 = 9.21

Metric tire sizes are stated as three numbers. The way it reads is:

width / aspect ratio R tire rim size
235 / 75 R 15