Metric to Standard Conversion
Enter the metric size (i.e. 285/75 R17)
15-inch Wheel Conversion Chart
| Metric | Standard |
|---|---|
| 215/75/15 | 27.7"x 8.5" |
| 225/70/15 | 27.4"x 8.9" |
| 225/75/15 | 28.3"x 8.9" |
| 235/75/15 | 29.0"x 9.3" |
| 245/75/15 | 29.5"x 9.6" |
| 255/75/15 | 30.0"x 10.0" |
| 265/75/15 | 30.6"x 10.4" |
16-inch Wheel Conversion Chart
| Metric | Standard |
|---|---|
| 205/85/16 | 29.7"x 8.1" |
| 215/75/16 | 28.7"x 8.5" |
| 225/70/16 | 28.4"x 8.9" |
| 225/75/16 | 29.2"x 8.9" |
| 235/70/16 | 29.0"x 9.3" |
| 235/85/16 | 31.7"x 9.3" |
| 245/70/16 | 29.5"x 9.6" |
| 245/75/16 | 30.5"x 9.6" |
| 255/70/16 | 30.0"x 10.0" |
| 265/70/16 | 30.6"x 10.4" |
| 265/75/16 | 31.6"x 10.4" |
| 275/70/16 | 31.2"x 10.8" |
| 285/75/16 | 32.8"x 11.2" |
| 295/75/16 | 33.4"x 11.6" |
| 305/70/16 | 33.0"x 12.2" |
| 315/75/16 | 34.8"x 12.4" |
| 375/55/16 | 32.8"x 15.5" |
| 395/70/16 | 37.9"x 16.0" |
17-inch Wheel Conversion Chart
| Metric | Standard |
|---|---|
| 245/70/17 | 30.6"x 9.8 |
| 265/70/17 | 31.6"x 10.7 |
| 285/70/17 | 33.0"x 11.5 |
| 315/70/17 | 34.4"x 12.4 |
18-inch Wheel Conversion Chart
| Metric | Standard |
|---|---|
| 275/65/18 | 32.1"x 11.0 |
| 375/50/18 | 33.0"x 15.4 |
| 325/60/18 | 33.2"x 13.3 |
| 325/65/18 | 34.8"x 13.5 |
| 305/70/18 | 35.0"x 12.2 |
| 375/60/18 | 35.7"x 15.5 |
| 395/65/18 | 37.8"x 15.7 |
20-inch Wheel Conversion Chart
| Metric | Standard |
|---|---|
| 325/50/20 | 33.0"x 13.2" |
225 = Section width in millimeters
70 = Aspect ratio (ratio of section height to section width)
R15 = Rim diameter
R = Radial Construction, B = Bias Construction, D = Bias Belted Construction
Calculations for Measurements
Tire Width: Section width divided by 25.4 (Ex: 225 / 25.4 = 8.86")
Section Height: Tire width times aspect ratio (Ex: 8.86" x 70% = 6.20")
Overall Diameter: Section height times 2 plus rim diameter (Ex: (6.20" x 2) + 15 = 27.40")
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