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285/70R20 tire size in inches
285/70R20 is 35.71" tall and 11.22" wide, and fits a 20" rim. In flotation (inch) sizing that is roughly 35.7x11.2R20.
285/70R20 dimensions
| Measurement | Inches | Metric |
|---|---|---|
| Overall diameter (height) | 35.71" | 907 mm |
| Section width | 11.22" | 285 mm |
| Sidewall height | 7.85" | 199.5 mm |
| Rim diameter | 20" | 508.0 mm |
| Circumference | 112.2" | 2849 mm |
| Revolutions per mile | 565 | |
| Aspect ratio | 70% (sidewall is 70% of the width) | |
Drawn to scale
Among the 131 sizes for 20" wheels on this site, 285/70R20 is #103 by height (shortest: 225/30R20, tallest: 365/85R20).
285/70R20 against the most popular 20" sizes
| Popular size | Height | Width | Sidewall | Speedo at true 60 |
|---|---|---|---|---|
| 275/60R20 | -2.72" (-7.62%) | -0.39" | -1.35" | 64.9 mph |
| 275/65R20 | -1.64" (-4.59%) | -0.39" | -0.81" | 62.9 mph |
| 275/55R20 | -3.80" (-10.64%) | -0.39" | -1.90" | 67.1 mph |
| 305/55R20 | -2.50" (-7%) | +0.79" | -1.25" | 64.5 mph |
| 295/65R20 | -0.61" (-1.71%) | +0.39" | -0.30" | 61 mph |
How the 285/70R20 numbers are worked out
The size code reads as 285 mm section width, 70% aspect ratio, R for radial construction and 20-inch wheel.
- Sidewall = 285 × 70% = 199.5 mm = 7.85"
- Diameter = 20" + 2 × 7.85" = 35.71"
- Circumference = π × 35.71" = 112.2"
- Revs per mile = 63,360" ÷ 112.2" = 565
Sizes that can replace 285/70R20 on a 20" wheel
Within 3% of 35.71". Last column: speedometer reading at a true 60 mph.
| Size | Diameter | Width | Difference | Speedo at true 60 mph |
|---|---|---|---|---|
| 265/75R20 | 35.65" | 10.43" | -0.17% | 60.1 mph |
| 305/65R20 | 35.61" | 12.01" | -0.28% | 60.2 mph |
| 335/60R20 | 35.83" | 13.19" | +0.34% | 59.8 mph |
| 280/70R20 | 35.43" | 11.02" | -0.78% | 60.5 mph |
| 355/55R20 | 35.37" | 13.98" | -0.95% | 60.6 mph |
| 325/60R20 | 35.35" | 12.80" | -1.01% | 60.6 mph |
| 315/65R20 | 36.12" | 12.40" | +1.15% | 59.3 mph |
| 275/75R20 | 36.24" | 10.83" | +1.48% | 59.1 mph |
| 375/55R20 | 36.24" | 14.76" | +1.48% | 59.1 mph |
| 275/70R20 | 35.16" | 10.83" | -1.54% | 60.9 mph |
| 295/70R20 | 36.26" | 11.61" | +1.54% | 59.1 mph |
| 345/60R20 | 36.30" | 13.58" | +1.65% | 59 mph |
One size wider or narrower
- Narrower: 275/70R20 — 10.83" wide, 35.16" tall
- Wider: 295/70R20 — 11.61" wide, 36.26" tall
Same height on a different wheel size
- 295/85R16 16" (+0.08%)
- 335/75R16 16" (+0.2%)
- 315/80R16 16" (+0.36%)
- 305/80R16 16" (-1.4%)
- 325/75R16 16" (-1.46%)
- 375/65R16 16" (-1.46%)
- 285/85R16 16" (-1.79%)
- 345/75R16 16" (+1.85%)
- 305/85R16 16" (+1.96%)
- 315/75R17 17" (-0.31%)
Questions about 285/70R20
How tall is a 285/70R20 tire in inches?
A 285/70R20 tire is 35.71 inches (907 mm) tall: the 20-inch rim plus two sidewalls of 7.85 inches each.
Is 285/70R20 a 36 inch tire?
Yes. At 35.71 inches tall it is commonly called a 36-inch tire.
How many revolutions per mile does a 285/70R20 make?
About 565 revolutions per mile, based on a calculated circumference of 112.2 inches.
What size can replace 285/70R20?
265/75R20 is the closest match on a 20" rim (-0.17% height). Check load index, speed rating and clearance first.
Compare 285/70R20 against any other size with the tire size calculator.