Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 245/30-21 | 225/40-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 26.79 (680.4) | 25.09 (637.2) | -1.7 (-43.2) -6.3% |
| Width inches (mm) | 9.65 (245) | 8.86 (225) | -0.79 (-20) -8.2% |
| Circum. inches (mm) | 84.16 (2137.54) | 78.81 (2001.82) | -5.34 (-135.72) -6.3% |
| Sidewall Height inches (mm) | 2.89 (73.5) | 3.54 (90) | 0.65 (16.5) 22.4% |
| Revolutions per mile (km) | 752.9 (467.83) | 803.94 (499.54) | 51.04 (31.72) 6.8% |
225/40-18 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 18.73 mph (30.14 km/h) |
| 25 mph (40.23 km/h) | 23.41 mph (37.68 km/h) |
| 30 mph (48.28 km/h) | 28.1 mph (45.21 km/h) |
| 35 mph (56.33 km/h) | 32.78 mph (52.75 km/h) |
| 40 mph (64.37 km/h) | 37.46 mph (60.29 km/h) |
| 45 mph (72.42 km/h) | 42.14 mph (67.82 km/h) |
| 50 mph (80.47 km/h) | 46.83 mph (75.36 km/h) |
| 55 mph (88.51 km/h) | 51.51 mph (82.89 km/h) |
| 60 mph (96.56 km/h) | 56.19 mph (90.43 km/h) |
| 65 mph (104.61 km/h) | 60.87 mph (97.97 km/h) |
| 70 mph (112.65 km/h) | 65.56 mph (105.5 km/h) |
| 75 mph (120.7 km/h) | 70.24 mph (113.04 km/h) |
| 80 mph (128.75 km/h) | 74.92 mph (120.57 km/h) |
| 85 mph (136.79 km/h) | 79.6 mph (128.11 km/h) |
| 90 mph (144.84 km/h) | 84.29 mph (135.64 km/h) |
| 95 mph (152.89 km/h) | 88.97 mph (143.18 km/h) |
| 100 mph (160.93 km/h) | 93.65 mph (150.72 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2046 | 2377 | 2560 | 2673 | 2795 | 2882 | 2977 | 3091 | 3247 | 3404 | 3578 | 3717 | 3970 | 4248 | 4466 | 4605 | 4684 | 4971 | 5372 | 6242 |
Better Fuel Economy Factory Ratios Increased Power
