METRIC TIRE SIZE CONVERSION CHART
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
P-Metric Size Actual Tire Width Actual Tire Height
15-inch rims 205/70R15 8.7 inches 26.2 inches
215/75R15 8.46 inches 27.6 inches
235/75R15 9.25 inches 28.8 inches
265/70R15 10.4 inches 29.6 inches
16-inch rims 245/75R16 9.64 inches 30.4 inches
285/75R16 11.2 inches 32.8 inches
315/75R16 12.4 inches 34.6 inches
395/70R16 15.5 inches 37.7 inches
17-inch rims 235/65R17 9.25 inches 29.5 inches
265/70R17 10.4 inches 31.6 inches
255/75R17 10.4 inches 32.0 inches
285/70R17 11.2 inches 32.7 inches
315/70R17 12.4 inches 34.3 inches
