Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/45-21 | 315/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 31.1 (789.9) | 30.92 (785.4) | -0.18 (-4.5) -0.6% |
| Width inches (mm) | 11.22 (285) | 12.4 (315) | 1.18 (30) 10.5% |
| Circum. inches (mm) | 97.7 (2481.54) | 97.14 (2467.41) | -0.56 (-14.14) -0.6% |
| Sidewall Height inches (mm) | 5.05 (128.25) | 4.96 (126) | -0.09 (-2.25) -1.8% |
| Revolutions per mile (km) | 648.53 (402.97) | 652.24 (405.28) | 3.72 (2.31) 0.6% |
315/40-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.89 mph (32 km/h) |
| 25 mph (40.23 km/h) | 24.86 mph (40 km/h) |
| 30 mph (48.28 km/h) | 29.83 mph (48.01 km/h) |
| 35 mph (56.33 km/h) | 34.8 mph (56.01 km/h) |
| 40 mph (64.37 km/h) | 39.77 mph (64.01 km/h) |
| 45 mph (72.42 km/h) | 44.74 mph (72.01 km/h) |
| 50 mph (80.47 km/h) | 49.72 mph (80.01 km/h) |
| 55 mph (88.51 km/h) | 54.69 mph (88.01 km/h) |
| 60 mph (96.56 km/h) | 59.66 mph (96.01 km/h) |
| 65 mph (104.61 km/h) | 64.63 mph (104.01 km/h) |
| 70 mph (112.65 km/h) | 69.6 mph (112.01 km/h) |
| 75 mph (120.7 km/h) | 74.57 mph (120.01 km/h) |
| 80 mph (128.75 km/h) | 79.54 mph (128.01 km/h) |
| 85 mph (136.79 km/h) | 84.52 mph (136.02 km/h) |
| 90 mph (144.84 km/h) | 89.49 mph (144.02 km/h) |
| 95 mph (152.89 km/h) | 94.46 mph (152.02 km/h) |
| 100 mph (160.93 km/h) | 99.43 mph (160.02 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1660 | 1928 | 2077 | 2168 | 2267 | 2338 | 2416 | 2507 | 2635 | 2762 | 2903 | 3016 | 3221 | 3447 | 3623 | 3736 | 3800 | 4033 | 4358 | 5064 |
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