285/45R20 tire size
285/45R20 is a metric size: 30.1" tall, 11.2" wide, on a 20" rim — about a 30x11.00R20. The sidewall is 5.0" and the tire turns 670 times per mile.
285/45R20 specs
| Overall diameter (height) | 30.10" · 764 mm |
|---|---|
| Section width | 11.22" · 285 mm |
| Sidewall height | 5.05" · 128 mm (45% of width) |
| Rim diameter | 20" |
| Circumference | 94.56" · 2.402 m |
| Revolutions per mile | 670 (416 per km) |
| Inch (flotation) equivalent | 30x11.00R20 |
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 | |
|---|---|---|---|---|---|
| 245/45R20 common | 28.68" | -4.71% | -40 mm | 57.2 mph | compare → |
| 255/45R20 common | 29.04" | -3.53% | -30 mm | 57.9 mph | compare → |
| 255/50R20 common | 30.04" | -0.20% | -30 mm | 59.9 mph | compare → |
| 275/40R20 common | 28.66" | -4.77% | -10 mm | 57.1 mph | compare → |
| 265/50R20 common | 30.43" | +1.11% | -20 mm | 60.7 mph | compare → |
| 245/50R20 common | 29.65" | -1.50% | -40 mm | 59.1 mph | compare → |
| 275/45R20 common | 29.74" | -1.18% | -10 mm | 59.3 mph | compare → |
| 255/55R20 common | 31.04" | +3.14% | -30 mm | 61.9 mph | compare → |
| 235/55R20 common | 30.18" | +0.26% | -50 mm | 60.2 mph | compare → |
| 265/45R20 common | 29.39" | -2.35% | -20 mm | 58.6 mph | compare → |
| 315/35R20 common | 28.68" | -4.71% | +30 mm | 57.2 mph | compare → |
| 275/50R20 common | 30.83" | +2.42% | -10 mm | 61.5 mph | compare → |
| 295/40R20 | 29.29" | -2.68% | +10 mm | 58.4 mph | compare → |
| 285/50R20 | 31.22" | +3.73% | 0 mm | 62.2 mph | compare → |
| 285/40R20 | 28.98" | -3.73% | 0 mm | 57.8 mph | compare → |
| 245/60R20 | 31.57" | +4.91% | -40 mm | 62.9 mph | compare → |
| 235/50R20 | 29.25" | -2.81% | -50 mm | 58.3 mph | compare → |
| 295/45R20 | 30.45" | +1.18% | +10 mm | 60.7 mph | compare → |
| 305/40R20 | 29.61" | -1.64% | +20 mm | 59.0 mph | compare → |
| 235/60R20 | 31.10" | +3.34% | -50 mm | 62.0 mph | calculate → |
| 325/35R20 | 28.96" | -3.79% | +40 mm | 57.7 mph | calculate → |
| 305/45R20 | 30.81" | +2.35% | +20 mm | 61.4 mph | calculate → |
| 31x18.00R20 | 31.00" | +3.00% | +172 mm | 61.8 mph | calculate → |
| 29x15.00R20 | 29.00" | -3.65% | +96 mm | 57.8 mph | calculate → |
| 29x18.00R20 | 29.00" | -3.65% | +172 mm | 57.8 mph | calculate → |
| 265/55R20 | 31.48" | +4.58% | -20 mm | 62.7 mph | calculate → |
| 175/70R20 | 29.65" | -1.50% | -110 mm | 59.1 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 | |
|---|---|---|---|---|---|
| 255/55R19 common | 30.04" | -0.18% | -30 mm | 59.9 mph | compare → |
| 295/40R21 | 30.29" | +0.64% | +10 mm | 60.4 mph | compare → |
| 285/40R21 | 29.98" | -0.41% | 0 mm | 59.8 mph | compare → |
| 265/45R21 | 30.39" | +0.97% | -20 mm | 60.6 mph | compare → |
| 255/45R21 | 30.04" | -0.21% | -30 mm | 59.9 mph | compare → |
| 275/50R19 | 29.83" | -0.90% | -10 mm | 59.5 mph | compare → |
| 235/50R21 | 30.25" | +0.51% | -50 mm | 60.3 mph | calculate → |
| 235/60R19 | 30.10" | +0.01% | -50 mm | 60.0 mph | calculate → |
| 175/80R19 | 30.02" | -0.25% | -110 mm | 59.9 mph | calculate → |
Try another size against 285/45R20
Questions
What size is 285/45R20 in inches?
285/45R20 is about 30.1" tall and 11.2" wide on a 20-inch rim — roughly a 30x11.00R20 in inch sizing.
What does 285/45R20 mean?
285 mm section width, sidewall 45% of the width (5.05"), radial construction, 20-inch rim.
What tire sizes are equivalent to 285/45R20?
On the same 20" rim, within 3% of the diameter: 255/50R20 (-0.20%), 235/55R20 (+0.26%), 265/50R20 (+1.11%), 275/45R20 (-1.18%), 295/45R20 (+1.18%), 175/70R20 (-1.50%).
How many revolutions per mile does a 285/45R20 tire make?
About 670 revolutions per mile (circumference 94.6").
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.