285/55R20 in inches & centimeters
Reference size: 285/55R20 has a nominal diameter of 32.34 inches and width of 11.22 inches, with a 6.17-inch sidewall on a 20-inch wheel.
This reference is available in English. ES / PT open the translated calculator with this size.
Convert this size or compare another
Nominal dimensions · 285/55R20
Side view
DOverall diameter32.34 in82.15 cm
SSidewall height6.17 in15.68 cm
WDWheel diameter20.00 in50.80 cm
Front view
DOverall diameter32.34 in82.15 cm
WSection width11.22 in28.50 cm
- DOverall diameter
- 32.34 in82.15 cm
- WSection width
- 11.22 in28.50 cm
- SSidewall height
- 6.17 in15.68 cm
- WDWheel diameter
- 20.00 in50.80 cm
- CCircumference
- 101.61 in258.08 cm
Approximate inch notation≈ 32.34 × 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.
Add a second size to compare dimensions and speedometer changes.
Speedometer
Add a second tire size to use this comparison.
Wheels
Enter wheel width, offset and spacer thickness for each setup.
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 285/55R20
Reference size: 285/55R20
| Measurement | inches | centimeters | millimeters |
|---|---|---|---|
| Overall diameter | 32.34 in | 82.15 cm | 821.5 mm |
| Section width | 11.22 in | 28.50 cm | 285.0 mm |
| Sidewall height | 6.17 in | 15.68 cm | 156.8 mm |
| Circumference | 101.61 in | 258.08 cm | 2,580.8 mm |
| Wheel diameter | 20.00 in | 50.80 cm | 508.0 mm |
| Revolutions / mi | 623.6 | ||
| Revolutions / km | 387.5 | ||
How we calculate it
285 = section width in millimeters; 55 = sidewall as a percentage of width; 20 = wheel diameter in inches.
Sidewall height: 285 × 55/100 = 156.75 mm
Overall diameter: (20 × 25.4) + (2 × 156.75) = 821.5 mm
Circumference: π × 821.5 ≈ 2,580.8 mm
Read the size-code guide Overall diameter: (20 × 25.4) + (2 × 156.75) = 821.5 mm
Circumference: π × 821.5 ≈ 2,580.8 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 285/55R20
Sorted by nominal diameter difference. Compare the tire maker’s published dimensions for the sizes you shortlist.