Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 275/30-21 | 255/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.5 (698.4) | 27.02 (686.4) | -0.47 (-12) -1.7% |
| Width inches (mm) | 10.83 (275) | 10.04 (255) | -0.79 (-20) -7.3% |
| Circum. inches (mm) | 86.38 (2194.09) | 84.9 (2156.39) | -1.48 (-37.7) -1.7% |
| Sidewall Height inches (mm) | 3.25 (82.5) | 3.01 (76.5) | -0.24 (-6) -7.3% |
| Revolutions per mile (km) | 733.49 (455.77) | 746.31 (463.74) | 12.82 (7.97) 1.7% |
255/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.66 mph (31.63 km/h) |
| 25 mph (40.23 km/h) | 24.57 mph (39.54 km/h) |
| 30 mph (48.28 km/h) | 29.48 mph (47.45 km/h) |
| 35 mph (56.33 km/h) | 34.4 mph (55.36 km/h) |
| 40 mph (64.37 km/h) | 39.31 mph (63.27 km/h) |
| 45 mph (72.42 km/h) | 44.23 mph (71.18 km/h) |
| 50 mph (80.47 km/h) | 49.14 mph (79.08 km/h) |
| 55 mph (88.51 km/h) | 54.05 mph (86.99 km/h) |
| 60 mph (96.56 km/h) | 58.97 mph (94.9 km/h) |
| 65 mph (104.61 km/h) | 63.88 mph (102.81 km/h) |
| 70 mph (112.65 km/h) | 68.8 mph (110.72 km/h) |
| 75 mph (120.7 km/h) | 73.71 mph (118.63 km/h) |
| 80 mph (128.75 km/h) | 78.63 mph (126.54 km/h) |
| 85 mph (136.79 km/h) | 83.54 mph (134.44 km/h) |
| 90 mph (144.84 km/h) | 88.45 mph (142.35 km/h) |
| 95 mph (152.89 km/h) | 93.37 mph (150.26 km/h) |
| 100 mph (160.93 km/h) | 98.28 mph (158.17 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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