Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 275/25-21 | 255/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 26.41 (670.9) | 27.02 (686.4) | 0.61 (15.5) 2.3% |
| Width inches (mm) | 10.83 (275) | 10.04 (255) | -0.79 (-20) -7.3% |
| Circum. inches (mm) | 82.98 (2107.69) | 84.9 (2156.39) | 1.92 (48.69) 2.3% |
| Sidewall Height inches (mm) | 2.71 (68.75) | 3.01 (76.5) | 0.31 (7.75) 11.3% |
| Revolutions per mile (km) | 763.56 (474.45) | 746.31 (463.74) | -17.24 (-10.71) -2.3% |
255/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.46 mph (32.93 km/h) |
| 25 mph (40.23 km/h) | 25.58 mph (41.16 km/h) |
| 30 mph (48.28 km/h) | 30.69 mph (49.4 km/h) |
| 35 mph (56.33 km/h) | 35.81 mph (57.63 km/h) |
| 40 mph (64.37 km/h) | 40.92 mph (65.86 km/h) |
| 45 mph (72.42 km/h) | 46.04 mph (74.09 km/h) |
| 50 mph (80.47 km/h) | 51.16 mph (82.33 km/h) |
| 55 mph (88.51 km/h) | 56.27 mph (90.56 km/h) |
| 60 mph (96.56 km/h) | 61.39 mph (98.79 km/h) |
| 65 mph (104.61 km/h) | 66.5 mph (107.02 km/h) |
| 70 mph (112.65 km/h) | 71.62 mph (115.26 km/h) |
| 75 mph (120.7 km/h) | 76.73 mph (123.49 km/h) |
| 80 mph (128.75 km/h) | 81.85 mph (131.72 km/h) |
| 85 mph (136.79 km/h) | 86.96 mph (139.95 km/h) |
| 90 mph (144.84 km/h) | 92.08 mph (148.19 km/h) |
| 95 mph (152.89 km/h) | 97.19 mph (156.42 km/h) |
| 100 mph (160.93 km/h) | 102.31 mph (164.65 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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