Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/40-21 | 285/45-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.98 (761.4) | 31.1 (789.9) | 1.12 (28.5) 3.7% |
| Width inches (mm) | 11.22 (285) | 11.22 (285) | 0 (0) 0% |
| Circum. inches (mm) | 94.17 (2392.01) | 97.7 (2481.54) | 3.53 (89.54) 3.7% |
| Sidewall Height inches (mm) | 4.49 (114) | 5.05 (128.25) | 0.56 (14.25) 12.5% |
| Revolutions per mile (km) | 672.8 (418.06) | 648.53 (402.97) | -24.27 (-15.08) -3.6% |
285/45-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.75 mph (33.39 km/h) |
| 25 mph (40.23 km/h) | 25.94 mph (41.74 km/h) |
| 30 mph (48.28 km/h) | 31.12 mph (50.09 km/h) |
| 35 mph (56.33 km/h) | 36.31 mph (58.44 km/h) |
| 40 mph (64.37 km/h) | 41.5 mph (66.78 km/h) |
| 45 mph (72.42 km/h) | 46.68 mph (75.13 km/h) |
| 50 mph (80.47 km/h) | 51.87 mph (83.48 km/h) |
| 55 mph (88.51 km/h) | 57.06 mph (91.83 km/h) |
| 60 mph (96.56 km/h) | 62.25 mph (100.18 km/h) |
| 65 mph (104.61 km/h) | 67.43 mph (108.52 km/h) |
| 70 mph (112.65 km/h) | 72.62 mph (116.87 km/h) |
| 75 mph (120.7 km/h) | 77.81 mph (125.22 km/h) |
| 80 mph (128.75 km/h) | 82.99 mph (133.57 km/h) |
| 85 mph (136.79 km/h) | 88.18 mph (141.91 km/h) |
| 90 mph (144.84 km/h) | 93.37 mph (150.26 km/h) |
| 95 mph (152.89 km/h) | 98.56 mph (158.61 km/h) |
| 100 mph (160.93 km/h) | 103.74 mph (166.96 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1650 | 1917 | 2065 | 2156 | 2254 | 2325 | 2402 | 2493 | 2620 | 2746 | 2886 | 2999 | 3202 | 3427 | 3603 | 3715 | 3778 | 4010 | 4333 | 5035 |
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