Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/25-20 | 285/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 25.61 (650.5) | 27.73 (704.4) | 2.12 (53.9) 8.3% |
| Width inches (mm) | 11.22 (285) | 11.22 (285) | 0 (0) 0% |
| Circum. inches (mm) | 80.46 (2043.61) | 87.12 (2212.94) | 6.67 (169.33) 8.3% |
| Sidewall Height inches (mm) | 2.81 (71.25) | 3.37 (85.5) | 0.56 (14.25) 20% |
| Revolutions per mile (km) | 787.5 (489.33) | 727.24 (451.89) | -60.26 (-37.44) -7.7% |
285/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.66 mph (34.85 km/h) |
| 25 mph (40.23 km/h) | 27.07 mph (43.57 km/h) |
| 30 mph (48.28 km/h) | 32.49 mph (52.28 km/h) |
| 35 mph (56.33 km/h) | 37.9 mph (60.99 km/h) |
| 40 mph (64.37 km/h) | 43.31 mph (69.71 km/h) |
| 45 mph (72.42 km/h) | 48.73 mph (78.42 km/h) |
| 50 mph (80.47 km/h) | 54.14 mph (87.13 km/h) |
| 55 mph (88.51 km/h) | 59.56 mph (95.85 km/h) |
| 60 mph (96.56 km/h) | 64.97 mph (104.56 km/h) |
| 65 mph (104.61 km/h) | 70.39 mph (113.28 km/h) |
| 70 mph (112.65 km/h) | 75.8 mph (121.99 km/h) |
| 75 mph (120.7 km/h) | 81.21 mph (130.7 km/h) |
| 80 mph (128.75 km/h) | 86.63 mph (139.42 km/h) |
| 85 mph (136.79 km/h) | 92.04 mph (148.13 km/h) |
| 90 mph (144.84 km/h) | 97.46 mph (156.84 km/h) |
| 95 mph (152.89 km/h) | 102.87 mph (165.56 km/h) |
| 100 mph (160.93 km/h) | 108.29 mph (174.27 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1851 | 2150 | 2315 | 2418 | 2528 | 2607 | 2693 | 2796 | 2937 | 3079 | 3237 | 3363 | 3591 | 3843 | 4040 | 4166 | 4237 | 4497 | 4859 | 5647 |
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