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305/50R20 tire size in inches
305/50R20 is 32.01" tall and 12.01" wide, and fits a 20" rim. In flotation (inch) sizing that is roughly 32.0x12.0R20.
305/50R20 dimensions
| Measurement | Inches | Metric |
|---|---|---|
| Overall diameter (height) | 32.01" | 813 mm |
| Section width | 12.01" | 305 mm |
| Sidewall height | 6.00" | 152.5 mm |
| Rim diameter | 20" | 508.0 mm |
| Circumference | 100.6" | 2554 mm |
| Revolutions per mile | 630 | |
| Aspect ratio | 50% (sidewall is 50% of the width) | |
Drawn to scale
Among the 131 sizes for 20" wheels on this site, 305/50R20 is #60 by height (shortest: 225/30R20, tallest: 365/85R20).
What people compare 305/50R20 with
Real comparisons drivers search for, worked out against 305/50R20:
| Compared size | Height | Width | Sidewall | Speedo at true 60 |
|---|---|---|---|---|
| 305/55R20 | +1.20" (+3.75%) | 0.00" | +0.60" | 57.8 mph |
| 275/55R20 | -0.10" (-0.31%) | -1.18" | -0.05" | 60.2 mph |
| 275/60R20 | +0.98" (+3.06%) | -1.18" | +0.50" | 58.2 mph |
How the 305/50R20 numbers are worked out
The size code reads as 305 mm section width, 50% aspect ratio, R for radial construction and 20-inch wheel.
- Sidewall = 305 × 50% = 152.5 mm = 6.00"
- Diameter = 20" + 2 × 6.00" = 32.01"
- Circumference = π × 32.01" = 100.6"
- Revs per mile = 63,360" ÷ 100.6" = 630
Sizes that can replace 305/50R20 on a 20" wheel
Within 3% of 32.01". Last column: speedometer reading at a true 60 mph.
| Size | Diameter | Width | Difference | Speedo at true 60 mph |
|---|---|---|---|---|
| 235/65R20 | 32.03" | 9.25" | +0.06% | 60 mph |
| 255/60R20 | 32.05" | 10.04" | +0.12% | 59.9 mph |
| 275/55R20 | 31.91" | 10.83" | -0.31% | 60.2 mph |
| 260/60R20 | 32.28" | 10.24" | +0.84% | 59.5 mph |
| 270/55R20 | 31.69" | 10.63" | -1% | 60.6 mph |
| 285/55R20 | 32.34" | 11.22" | +1.03% | 59.4 mph |
| 315/50R20 | 32.40" | 12.40" | +1.22% | 59.3 mph |
| 295/50R20 | 31.61" | 11.61" | -1.25% | 60.8 mph |
| 245/60R20 | 31.57" | 9.65" | -1.37% | 60.8 mph |
| 325/45R20 | 31.52" | 12.80" | -1.53% | 60.9 mph |
| 265/60R20 | 32.52" | 10.43" | +1.59% | 59.1 mph |
| 265/55R20 | 31.48" | 10.43" | -1.66% | 61 mph |
One size wider or narrower
- Narrower: 295/50R20 — 11.61" wide, 31.61" tall
- Wider: 315/50R20 — 12.40" wide, 32.40" tall
Same height on a different wheel size
- 255/85R15 15" (+0.19%)
- 285/75R15 15" (-0.56%)
- 305/70R15 15" (-0.62%)
- 265/80R15 15" (-1%)
- 315/70R15 15" (+1.09%)
- 295/75R15 15" (+1.28%)
- 245/85R15 15" (-1.91%)
- 255/80R16 16" (+0.16%)
- 270/75R16 16" (-0.22%)
- 315/65R16 16" (+0.34%)
Questions about 305/50R20
How tall is a 305/50R20 tire in inches?
A 305/50R20 tire is 32.01 inches (813 mm) tall: the 20-inch rim plus two sidewalls of 6.00 inches each.
Is 305/50R20 a 32 inch tire?
Yes. At 32.01 inches tall it is commonly called a 32-inch tire.
How many revolutions per mile does a 305/50R20 make?
About 630 revolutions per mile, based on a calculated circumference of 100.6 inches.
What size can replace 305/50R20?
235/65R20 is the closest match on a 20" rim (+0.06% height). Check load index, speed rating and clearance first.
Compare 305/50R20 against any other size with the tire size calculator.