305/50R20 tire size
305/50R20 is a metric size: 32.0" tall, 12.0" wide, on a 20" rim — about a 32x12.00R20. The sidewall is 6.0" and the tire turns 630 times per mile.
305/50R20 specs
| Overall diameter (height) | 32.01" · 813 mm |
|---|---|
| Section width | 12.01" · 305 mm |
| Sidewall height | 6.00" · 153 mm (50% of width) |
| Rim diameter | 20" |
| Circumference | 100.56" · 2.554 m |
| Revolutions per mile | 630 (392 per km) |
| Inch (flotation) equivalent | 32x12.00R20 |
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" | -0.31% | -30 mm | 59.8 mph | compare → |
| 275/60R20 common | 32.99" | +3.08% | -30 mm | 61.8 mph | compare → |
| 265/50R20 common | 30.43" | -4.92% | -40 mm | 57.0 mph | compare → |
| 255/55R20 common | 31.04" | -3.01% | -50 mm | 58.2 mph | compare → |
| 265/60R20 common | 32.52" | +1.60% | -40 mm | 61.0 mph | compare → |
| 305/55R20 common | 33.21" | +3.75% | 0 mm | 62.3 mph | compare → |
| 285/55R20 common | 32.34" | +1.05% | -20 mm | 60.6 mph | compare → |
| 285/60R20 common | 33.46" | +4.55% | -20 mm | 62.7 mph | compare → |
| 275/50R20 common | 30.83" | -3.69% | -30 mm | 57.8 mph | compare → |
| 33x12.50R20 common | 33.00" | +3.10% | +13 mm | 61.9 mph | compare → |
| 295/55R20 | 32.78" | +2.40% | -10 mm | 61.4 mph | compare → |
| 285/50R20 | 31.22" | -2.46% | -20 mm | 58.5 mph | compare → |
| 245/60R20 | 31.57" | -1.35% | -60 mm | 59.2 mph | compare → |
| 295/45R20 | 30.45" | -4.86% | -10 mm | 57.1 mph | compare → |
| 255/60R20 | 32.05" | +0.12% | -50 mm | 60.1 mph | compare → |
| 235/60R20 | 31.10" | -2.83% | -70 mm | 58.3 mph | calculate → |
| 33x13.50R20 | 33.00" | +3.10% | +38 mm | 61.9 mph | calculate → |
| 33x11.50R20 | 33.00" | +3.10% | -13 mm | 61.9 mph | calculate → |
| 265/55R20 | 31.48" | -1.66% | -40 mm | 59.0 mph | calculate → |
| 325/50R20 | 32.80" | +2.46% | +20 mm | 61.5 mph | calculate → |
| 33x12.00R20 | 33.00" | +3.10% | 0 mm | 61.9 mph | calculate → |
| 33x22.00R20 | 33.00" | +3.10% | +254 mm | 61.9 mph | calculate → |
| 31x18.00R20 | 31.00" | -3.15% | +152 mm | 58.1 mph | calculate → |
| 305/45R20 | 30.81" | -3.75% | 0 mm | 57.7 mph | calculate → |
| 375/45R20 | 33.29" | +4.00% | +70 mm | 62.4 mph | calculate → |
| 295/50R20 | 31.61" | -1.23% | -10 mm | 59.3 mph | calculate → |
| 315/50R20 | 32.40" | +1.23% | +10 mm | 60.7 mph | calculate → |
| 33x14.50R20 | 33.00" | +3.10% | +63 mm | 61.9 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 | |
|---|---|---|---|---|---|
| 275/50R21 | 31.83" | -0.57% | -30 mm | 59.7 mph | compare → |
| 255/65R19 | 32.05" | +0.14% | -50 mm | 60.1 mph | calculate → |
| 315/45R21 | 32.16" | +0.48% | +10 mm | 60.3 mph | calculate → |
Try another size against 305/50R20
Questions
What size is 305/50R20 in inches?
305/50R20 is about 32.0" tall and 12.0" wide on a 20-inch rim — roughly a 32x12.00R20 in inch sizing.
What does 305/50R20 mean?
305 mm section width, sidewall 50% of the width (6.00"), radial construction, 20-inch rim.
What tire sizes are equivalent to 305/50R20?
On the same 20" rim, within 3% of the diameter: 255/60R20 (+0.12%), 275/55R20 (-0.31%), 285/55R20 (+1.05%), 295/50R20 (-1.23%), 315/50R20 (+1.23%), 245/60R20 (-1.35%).
How many revolutions per mile does a 305/50R20 tire make?
About 630 revolutions per mile (circumference 100.6").
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.