Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/45-21 | 325/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 31.1 (789.9) | 31.24 (793.4) | 0.14 (3.5) 0.4% |
| Width inches (mm) | 11.22 (285) | 12.8 (325) | 1.57 (40) 14% |
| Circum. inches (mm) | 97.7 (2481.54) | 98.13 (2492.54) | 0.43 (11) 0.4% |
| Sidewall Height inches (mm) | 5.05 (128.25) | 5.12 (130) | 0.07 (1.75) 1.4% |
| Revolutions per mile (km) | 648.53 (402.97) | 645.66 (401.2) | -2.86 (-1.78) -0.4% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.09 mph (32.33 km/h) |
| 25 mph (40.23 km/h) | 25.11 mph (40.41 km/h) |
| 30 mph (48.28 km/h) | 30.13 mph (48.49 km/h) |
| 35 mph (56.33 km/h) | 35.16 mph (56.58 km/h) |
| 40 mph (64.37 km/h) | 40.18 mph (64.66 km/h) |
| 45 mph (72.42 km/h) | 45.2 mph (72.74 km/h) |
| 50 mph (80.47 km/h) | 50.22 mph (80.82 km/h) |
| 55 mph (88.51 km/h) | 55.24 mph (88.91 km/h) |
| 60 mph (96.56 km/h) | 60.27 mph (96.99 km/h) |
| 65 mph (104.61 km/h) | 65.29 mph (105.07 km/h) |
| 70 mph (112.65 km/h) | 70.31 mph (113.15 km/h) |
| 75 mph (120.7 km/h) | 75.33 mph (121.24 km/h) |
| 80 mph (128.75 km/h) | 80.35 mph (129.32 km/h) |
| 85 mph (136.79 km/h) | 85.38 mph (137.4 km/h) |
| 90 mph (144.84 km/h) | 90.4 mph (145.48 km/h) |
| 95 mph (152.89 km/h) | 95.42 mph (153.57 km/h) |
| 100 mph (160.93 km/h) | 100.44 mph (161.65 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1643 | 1909 | 2056 | 2147 | 2244 | 2314 | 2391 | 2482 | 2608 | 2734 | 2874 | 2986 | 3188 | 3412 | 3587 | 3699 | 3762 | 3992 | 4314 | 5013 |
Better Fuel Economy Factory Ratios Increased Power
