Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/45-21 | 278/50-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 31.1 (789.9) | 30.94 (786) | -0.15 (-3.9) -0.5% |
| Width inches (mm) | 11.22 (285) | 10.94 (278) | -0.28 (-7) -2.5% |
| Circum. inches (mm) | 97.7 (2481.54) | 97.22 (2469.29) | -0.48 (-12.25) -0.5% |
| Sidewall Height inches (mm) | 5.05 (128.25) | 5.47 (139) | 0.42 (10.75) 8.4% |
| Revolutions per mile (km) | 648.53 (402.97) | 651.74 (404.97) | 3.22 (2) 0.5% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.9 mph (32.03 km/h) |
| 25 mph (40.23 km/h) | 24.88 mph (40.04 km/h) |
| 30 mph (48.28 km/h) | 29.85 mph (48.04 km/h) |
| 35 mph (56.33 km/h) | 34.83 mph (56.05 km/h) |
| 40 mph (64.37 km/h) | 39.8 mph (64.06 km/h) |
| 45 mph (72.42 km/h) | 44.78 mph (72.06 km/h) |
| 50 mph (80.47 km/h) | 49.75 mph (80.07 km/h) |
| 55 mph (88.51 km/h) | 54.73 mph (88.08 km/h) |
| 60 mph (96.56 km/h) | 59.7 mph (96.08 km/h) |
| 65 mph (104.61 km/h) | 64.68 mph (104.09 km/h) |
| 70 mph (112.65 km/h) | 69.65 mph (112.1 km/h) |
| 75 mph (120.7 km/h) | 74.63 mph (120.11 km/h) |
| 80 mph (128.75 km/h) | 79.61 mph (128.11 km/h) |
| 85 mph (136.79 km/h) | 84.58 mph (136.12 km/h) |
| 90 mph (144.84 km/h) | 89.56 mph (144.13 km/h) |
| 95 mph (152.89 km/h) | 94.53 mph (152.13 km/h) |
| 100 mph (160.93 km/h) | 99.51 mph (160.14 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1659 | 1927 | 2075 | 2167 | 2266 | 2336 | 2414 | 2505 | 2633 | 2760 | 2901 | 3014 | 3218 | 3444 | 3621 | 3734 | 3797 | 4030 | 4355 | 5060 |
Better Fuel Economy Factory Ratios Increased Power
