285/45R20 in inches & centimeters
Reference size: 285/45R20 has a nominal diameter of 30.10 inches and width of 11.22 inches, with a 5.05-inch sidewall on a 20-inch wheel.
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Nominal dimensions · 285/45R20
Side view
DOverall diameter30.10 in76.45 cm
SSidewall height5.05 in12.83 cm
WDWheel diameter20.00 in50.80 cm
Front view
DOverall diameter30.10 in76.45 cm
WSection width11.22 in28.50 cm
- DOverall diameter
- 30.10 in76.45 cm
- WSection width
- 11.22 in28.50 cm
- SSidewall height
- 5.05 in12.83 cm
- WDWheel diameter
- 20.00 in50.80 cm
- CCircumference
- 94.56 in240.17 cm
Approximate inch notation≈ 30.10 × 11.22R20
Diameter × width, with wheel diameter in inches, derived from the nominal size code. Use the tire maker’s catalog to choose an available product size.
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Nearby sizes
Compare these dimensions with the tire manufacturer’s published measurements and your vehicle’s tire and wheel specifications.
Detailed measurements and formulas for 285/45R20
Reference size: 285/45R20
| Measurement | inches | centimeters | millimeters |
|---|---|---|---|
| Overall diameter | 30.10 in | 76.45 cm | 764.5 mm |
| Section width | 11.22 in | 28.50 cm | 285.0 mm |
| Sidewall height | 5.05 in | 12.83 cm | 128.3 mm |
| Circumference | 94.56 in | 240.17 cm | 2,401.7 mm |
| Wheel diameter | 20.00 in | 50.80 cm | 508.0 mm |
| Revolutions / mi | 670.1 | ||
| Revolutions / km | 416.4 | ||
How we calculate it
285 = section width in millimeters; 45 = sidewall as a percentage of width; 20 = wheel diameter in inches.
Sidewall height: 285 × 45/100 = 128.25 mm
Overall diameter: (20 × 25.4) + (2 × 128.25) = 764.5 mm
Circumference: π × 764.5 ≈ 2,401.7 mm
Read the size-code guide Overall diameter: (20 × 25.4) + (2 × 128.25) = 764.5 mm
Circumference: π × 764.5 ≈ 2,401.7 mm
Reference model marked 245/40 ZR18 97Y.
Product image: Continental Tire
Tread-detail reference. Section width is calculated separately.
Product image: Continental TireWhat to check before changing size
Use the vehicle and tire specifications to check these three points:
- Vehicle placard and manual: match an approved size and the required load and speed ratings.
- Wheel specifications: check the tire maker’s wheel-width range and the wheel offset.
- Available space: check clearance at full steering lock and throughout suspension travel.
Method / data
Dimensions are calculated from the nominal size code. The reference catalog lists size codes; the tire maker’s specification sheet gives the exact model’s published measurements.
Calculation method and reference dataNearby sizes for 285/45R20
Sorted by nominal diameter difference. Compare the tire maker’s published dimensions for the sizes you shortlist.