285/50R20 tire size
285/50R20 is a metric size: 31.2" tall, 11.2" wide, on a 20" rim — about a 31x11.00R20. The sidewall is 5.6" and the tire turns 646 times per mile.
285/50R20 specs
| Overall diameter (height) | 31.22" · 793 mm |
|---|---|
| Section width | 11.22" · 285 mm |
| Sidewall height | 5.61" · 143 mm (50% of width) |
| Rim diameter | 20" |
| Circumference | 98.08" · 2.491 m |
| Revolutions per mile | 646 (401 per km) |
| Inch (flotation) equivalent | 31x11.00R20 |
Equivalent sizes on a 20" rim
Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 275/55R20 common | 31.91" | +2.21% | -10 mm | 61.3 mph | compare → |
| 255/50R20 common | 30.04" | -3.78% | -30 mm | 57.7 mph | compare → |
| 265/50R20 common | 30.43" | -2.52% | -20 mm | 58.5 mph | compare → |
| 275/45R20 common | 29.74" | -4.73% | -10 mm | 57.2 mph | compare → |
| 255/55R20 common | 31.04" | -0.57% | -30 mm | 59.7 mph | compare → |
| 235/55R20 common | 30.18" | -3.34% | -50 mm | 58.0 mph | compare → |
| 265/60R20 common | 32.52" | +4.16% | -20 mm | 62.5 mph | compare → |
| 285/55R20 common | 32.34" | +3.59% | 0 mm | 62.2 mph | compare → |
| 275/50R20 common | 30.83" | -1.26% | -10 mm | 59.2 mph | compare → |
| 295/55R20 | 32.78" | +4.98% | +10 mm | 63.0 mph | compare → |
| 245/60R20 | 31.57" | +1.13% | -40 mm | 60.7 mph | compare → |
| 305/50R20 | 32.01" | +2.52% | +20 mm | 61.5 mph | compare → |
| 285/45R20 | 30.10" | -3.59% | 0 mm | 57.8 mph | compare → |
| 295/45R20 | 30.45" | -2.46% | +10 mm | 58.5 mph | compare → |
| 255/60R20 | 32.05" | +2.65% | -30 mm | 61.6 mph | compare → |
| 235/60R20 | 31.10" | -0.38% | -50 mm | 59.8 mph | calculate → |
| 31x18.00R20 | 31.00" | -0.71% | +172 mm | 59.6 mph | calculate → |
| 265/55R20 | 31.48" | +0.82% | -20 mm | 60.5 mph | calculate → |
| 305/45R20 | 30.81" | -1.32% | +20 mm | 59.2 mph | calculate → |
| 295/50R20 | 31.61" | +1.26% | +10 mm | 60.8 mph | calculate → |
| 315/50R20 | 32.40" | +3.78% | +30 mm | 62.3 mph | calculate → |
Plus / minus sizing: 19" and 21" rims
Same overall height on a different rim. Check wheel width and clearance before switching.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 255/60R19 common | 31.05" | -0.55% | -30 mm | 59.7 mph | compare → |
| 285/45R21 | 31.10" | -0.39% | 0 mm | 59.8 mph | compare → |
| 275/55R19 | 30.91" | -1.00% | -10 mm | 59.4 mph | compare → |
| 315/40R21 | 30.92" | -0.96% | +30 mm | 59.4 mph | compare → |
| 255/50R21 | 31.04" | -0.58% | -30 mm | 59.7 mph | compare → |
| 235/65R19 | 31.03" | -0.62% | -50 mm | 59.6 mph | calculate → |
| 325/40R21 | 31.24" | +0.05% | +40 mm | 60.0 mph | calculate → |
Try another size against 285/50R20
Questions
What size is 285/50R20 in inches?
285/50R20 is about 31.2" tall and 11.2" wide on a 20-inch rim — roughly a 31x11.00R20 in inch sizing.
What does 285/50R20 mean?
285 mm section width, sidewall 50% of the width (5.61"), radial construction, 20-inch rim.
What tire sizes are equivalent to 285/50R20?
On the same 20" rim, within 3% of the diameter: 235/60R20 (-0.38%), 255/55R20 (-0.57%), 31x18.00R20 (-0.71%), 265/55R20 (+0.82%), 245/60R20 (+1.13%), 275/50R20 (-1.26%).
How many revolutions per mile does a 285/50R20 tire make?
About 646 revolutions per mile (circumference 98.1").
How these numbers are computed
Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.