315/50R20 tire size
315/50R20 is a metric size: 32.4" tall, 12.4" wide, on a 20" rim — about a 32.5x12.50R20. The sidewall is 6.2" and the tire turns 622 times per mile.
315/50R20 specs
| Overall diameter (height) | 32.40" · 823 mm |
|---|---|
| Section width | 12.40" · 315 mm |
| Sidewall height | 6.20" · 158 mm (50% of width) |
| Rim diameter | 20" |
| Circumference | 101.79" · 2.586 m |
| Revolutions per mile | 622 (387 per km) |
| Inch (flotation) equivalent | 32.5x12.50R20 |
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" | -1.52% | -40 mm | 59.1 mph | calculate → |
| 275/60R20 common | 32.99" | +1.82% | -40 mm | 61.1 mph | calculate → |
| 255/55R20 common | 31.04" | -4.19% | -60 mm | 57.5 mph | calculate → |
| 265/60R20 common | 32.52" | +0.36% | -50 mm | 60.2 mph | calculate → |
| 305/55R20 common | 33.21" | +2.49% | -10 mm | 61.5 mph | calculate → |
| 285/55R20 common | 32.34" | -0.18% | -30 mm | 59.9 mph | calculate → |
| 285/60R20 common | 33.46" | +3.28% | -30 mm | 62.0 mph | calculate → |
| 275/50R20 common | 30.83" | -4.86% | -40 mm | 57.1 mph | calculate → |
| 33x12.50R20 common | 33.00" | +1.85% | +3 mm | 61.1 mph | calculate → |
| 295/60R20 | 33.94" | +4.74% | -20 mm | 62.8 mph | calculate → |
| 295/55R20 | 32.78" | +1.15% | -20 mm | 60.7 mph | calculate → |
| 285/50R20 | 31.22" | -3.65% | -30 mm | 57.8 mph | calculate → |
| 245/60R20 | 31.57" | -2.55% | -70 mm | 58.5 mph | calculate → |
| 305/50R20 | 32.01" | -1.22% | -10 mm | 59.3 mph | calculate → |
| 255/60R20 | 32.05" | -1.09% | -60 mm | 59.3 mph | calculate → |
| 33x13.50R20 | 33.00" | +1.85% | +28 mm | 61.1 mph | calculate → |
| 235/60R20 | 31.10" | -4.01% | -80 mm | 57.6 mph | calculate → |
| 33x11.50R20 | 33.00" | +1.85% | -23 mm | 61.1 mph | calculate → |
| 325/50R20 | 32.80" | +1.22% | +10 mm | 60.7 mph | calculate → |
| 33x12.00R20 | 33.00" | +1.85% | -10 mm | 61.1 mph | calculate → |
| 33x22.00R20 | 33.00" | +1.85% | +244 mm | 61.1 mph | calculate → |
| 375/45R20 | 33.29" | +2.73% | +60 mm | 61.6 mph | calculate → |
| 265/55R20 | 31.48" | -2.86% | -50 mm | 58.3 mph | calculate → |
| 31x18.00R20 | 31.00" | -4.33% | +142 mm | 57.4 mph | calculate → |
| 305/45R20 | 30.81" | -4.92% | -10 mm | 57.0 mph | calculate → |
| 34x11.50R20 | 34.00" | +4.93% | -23 mm | 63.0 mph | calculate → |
| 33x14.50R20 | 33.00" | +1.85% | +53 mm | 61.1 mph | calculate → |
| 295/50R20 | 31.61" | -2.43% | -20 mm | 58.5 mph | calculate → |
| 355/50R20 | 33.98" | +4.86% | +40 mm | 62.9 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 | |
|---|---|---|---|---|---|
| 315/45R21 | 32.16" | -0.74% | 0 mm | 59.6 mph | calculate → |
Try another size against 315/50R20
Questions
What size is 315/50R20 in inches?
315/50R20 is about 32.4" tall and 12.4" wide on a 20-inch rim — roughly a 32.5x12.50R20 in inch sizing.
What does 315/50R20 mean?
315 mm section width, sidewall 50% of the width (6.20"), radial construction, 20-inch rim.
What tire sizes are equivalent to 315/50R20?
On the same 20" rim, within 3% of the diameter: 285/55R20 (-0.18%), 265/60R20 (+0.36%), 255/60R20 (-1.09%), 295/55R20 (+1.15%), 305/50R20 (-1.22%), 325/50R20 (+1.22%).
How many revolutions per mile does a 315/50R20 tire make?
About 622 revolutions per mile (circumference 101.8").
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.