Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/45-21 | 315/45-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 31.1 (789.9) | 32.16 (816.9) | 1.06 (27) 3.4% |
| Width inches (mm) | 11.22 (285) | 12.4 (315) | 1.18 (30) 10.5% |
| Circum. inches (mm) | 97.7 (2481.54) | 101.04 (2566.37) | 3.34 (84.82) 3.4% |
| Sidewall Height inches (mm) | 5.05 (128.25) | 5.58 (141.75) | 0.53 (13.5) 10.5% |
| Revolutions per mile (km) | 648.53 (402.97) | 627.09 (389.66) | -21.43 (-13.32) -3.3% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.68 mph (33.29 km/h) |
| 25 mph (40.23 km/h) | 25.85 mph (41.61 km/h) |
| 30 mph (48.28 km/h) | 31.03 mph (49.93 km/h) |
| 35 mph (56.33 km/h) | 36.2 mph (58.25 km/h) |
| 40 mph (64.37 km/h) | 41.37 mph (66.57 km/h) |
| 45 mph (72.42 km/h) | 46.54 mph (74.9 km/h) |
| 50 mph (80.47 km/h) | 51.71 mph (83.22 km/h) |
| 55 mph (88.51 km/h) | 56.88 mph (91.54 km/h) |
| 60 mph (96.56 km/h) | 62.05 mph (99.86 km/h) |
| 65 mph (104.61 km/h) | 67.22 mph (108.18 km/h) |
| 70 mph (112.65 km/h) | 72.39 mph (116.5 km/h) |
| 75 mph (120.7 km/h) | 77.56 mph (124.83 km/h) |
| 80 mph (128.75 km/h) | 82.73 mph (133.15 km/h) |
| 85 mph (136.79 km/h) | 87.91 mph (141.47 km/h) |
| 90 mph (144.84 km/h) | 93.08 mph (149.79 km/h) |
| 95 mph (152.89 km/h) | 98.25 mph (158.11 km/h) |
| 100 mph (160.93 km/h) | 103.42 mph (166.44 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1596 | 1854 | 1996 | 2085 | 2180 | 2248 | 2322 | 2411 | 2533 | 2655 | 2791 | 2900 | 3097 | 3314 | 3484 | 3592 | 3653 | 3878 | 4190 | 4869 |
Better Fuel Economy Factory Ratios Increased Power
