Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/45-21 | 255/50-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 31.1 (789.9) | 30.04 (763) | -1.06 (-26.9) -3.4% |
| Width inches (mm) | 11.22 (285) | 10.04 (255) | -1.18 (-30) -10.5% |
| Circum. inches (mm) | 97.7 (2481.54) | 94.37 (2397.04) | -3.33 (-84.51) -3.4% |
| Sidewall Height inches (mm) | 5.05 (128.25) | 5.02 (127.5) | -0.03 (-0.75) -0.6% |
| Revolutions per mile (km) | 648.53 (402.97) | 671.39 (417.18) | 22.86 (14.21) 3.5% |
255/50-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.32 mph (31.09 km/h) |
| 25 mph (40.23 km/h) | 24.15 mph (38.86 km/h) |
| 30 mph (48.28 km/h) | 28.98 mph (46.64 km/h) |
| 35 mph (56.33 km/h) | 33.81 mph (54.41 km/h) |
| 40 mph (64.37 km/h) | 38.64 mph (62.18 km/h) |
| 45 mph (72.42 km/h) | 43.47 mph (69.95 km/h) |
| 50 mph (80.47 km/h) | 48.3 mph (77.73 km/h) |
| 55 mph (88.51 km/h) | 53.13 mph (85.5 km/h) |
| 60 mph (96.56 km/h) | 57.96 mph (93.27 km/h) |
| 65 mph (104.61 km/h) | 62.79 mph (101.05 km/h) |
| 70 mph (112.65 km/h) | 67.62 mph (108.82 km/h) |
| 75 mph (120.7 km/h) | 72.45 mph (116.59 km/h) |
| 80 mph (128.75 km/h) | 77.28 mph (124.36 km/h) |
| 85 mph (136.79 km/h) | 82.11 mph (132.14 km/h) |
| 90 mph (144.84 km/h) | 86.94 mph (139.91 km/h) |
| 95 mph (152.89 km/h) | 91.76 mph (147.68 km/h) |
| 100 mph (160.93 km/h) | 96.59 mph (155.45 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1709 | 1985 | 2138 | 2232 | 2334 | 2407 | 2486 | 2581 | 2712 | 2843 | 2988 | 3104 | 3315 | 3548 | 3730 | 3846 | 3912 | 4151 | 4486 | 5213 |
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