Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 305/25-21 | 305/30-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27 (685.9) | 27.2 (691) | 0.2 (5.1) 0.7% |
| Width inches (mm) | 12.01 (305) | 12.01 (305) | 0 (0) 0% |
| Circum. inches (mm) | 84.84 (2154.82) | 85.47 (2170.84) | 0.63 (16.02) 0.7% |
| Sidewall Height inches (mm) | 3 (76.25) | 3.6 (91.5) | 0.6 (15.25) 20% |
| Revolutions per mile (km) | 746.86 (464.08) | 741.35 (460.65) | -5.51 (-3.43) -0.7% |
305/30-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.15 mph (32.43 km/h) |
| 25 mph (40.23 km/h) | 25.19 mph (40.53 km/h) |
| 30 mph (48.28 km/h) | 30.22 mph (48.64 km/h) |
| 35 mph (56.33 km/h) | 35.26 mph (56.75 km/h) |
| 40 mph (64.37 km/h) | 40.3 mph (64.85 km/h) |
| 45 mph (72.42 km/h) | 45.33 mph (72.96 km/h) |
| 50 mph (80.47 km/h) | 50.37 mph (81.07 km/h) |
| 55 mph (88.51 km/h) | 55.41 mph (89.17 km/h) |
| 60 mph (96.56 km/h) | 60.45 mph (97.28 km/h) |
| 65 mph (104.61 km/h) | 65.48 mph (105.39 km/h) |
| 70 mph (112.65 km/h) | 70.52 mph (113.49 km/h) |
| 75 mph (120.7 km/h) | 75.56 mph (121.6 km/h) |
| 80 mph (128.75 km/h) | 80.59 mph (129.71 km/h) |
| 85 mph (136.79 km/h) | 85.63 mph (137.81 km/h) |
| 90 mph (144.84 km/h) | 90.67 mph (145.92 km/h) |
| 95 mph (152.89 km/h) | 95.71 mph (154.02 km/h) |
| 100 mph (160.93 km/h) | 100.74 mph (162.13 km/h) |
| 2.35 | 2.73 | 2.94 | 3.07 | 3.21 | 3.31 | 3.42 | 3.55 | 3.73 | 3.91 | 4.11 | 4.27 | 4.56 | 4.88 | 5.13 | 5.29 | 5.38 | 5.71 | 6.17 | 7.17 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1887 | 2192 | 2360 | 2465 | 2577 | 2657 | 2746 | 2850 | 2994 | 3139 | 3300 | 3428 | 3661 | 3918 | 4118 | 4247 | 4319 | 4584 | 4953 | 5756 |
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