Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 305/25-21 | 255/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27 (685.9) | 27.02 (686.4) | 0.02 (0.5) 0.1% |
| Width inches (mm) | 12.01 (305) | 10.04 (255) | -1.97 (-50) -16.4% |
| Circum. inches (mm) | 84.84 (2154.82) | 84.9 (2156.39) | 0.06 (1.57) 0.1% |
| Sidewall Height inches (mm) | 3 (76.25) | 3.01 (76.5) | 0.01 (0.25) 0.3% |
| Revolutions per mile (km) | 746.86 (464.08) | 746.31 (463.74) | -0.54 (-0.34) -0.1% |
255/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.01 mph (32.21 km/h) |
| 25 mph (40.23 km/h) | 25.02 mph (40.26 km/h) |
| 30 mph (48.28 km/h) | 30.02 mph (48.32 km/h) |
| 35 mph (56.33 km/h) | 35.03 mph (56.37 km/h) |
| 40 mph (64.37 km/h) | 40.03 mph (64.42 km/h) |
| 45 mph (72.42 km/h) | 45.03 mph (72.47 km/h) |
| 50 mph (80.47 km/h) | 50.04 mph (80.53 km/h) |
| 55 mph (88.51 km/h) | 55.04 mph (88.58 km/h) |
| 60 mph (96.56 km/h) | 60.04 mph (96.63 km/h) |
| 65 mph (104.61 km/h) | 65.05 mph (104.68 km/h) |
| 70 mph (112.65 km/h) | 70.05 mph (112.74 km/h) |
| 75 mph (120.7 km/h) | 75.05 mph (120.79 km/h) |
| 80 mph (128.75 km/h) | 80.06 mph (128.84 km/h) |
| 85 mph (136.79 km/h) | 85.06 mph (136.89 km/h) |
| 90 mph (144.84 km/h) | 90.07 mph (144.95 km/h) |
| 95 mph (152.89 km/h) | 95.07 mph (153 km/h) |
| 100 mph (160.93 km/h) | 100.07 mph (161.05 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1899 | 2206 | 2376 | 2481 | 2594 | 2675 | 2764 | 2869 | 3015 | 3160 | 3322 | 3451 | 3685 | 3944 | 4146 | 4275 | 4348 | 4615 | 4986 | 5795 |
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