Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 145/70-18 | 255/40-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 25.99 (660.2) | 28.03 (712) | 2.04 (51.8) 7.8% |
| Width inches (mm) | 5.71 (145) | 10.04 (255) | 4.33 (110) 75.9% |
| Circum. inches (mm) | 81.66 (2074.08) | 88.06 (2236.81) | 6.41 (162.73) 7.8% |
| Sidewall Height inches (mm) | 4 (101.5) | 4.02 (102) | 0.02 (0.5) 0.5% |
| Revolutions per mile (km) | 775.93 (482.14) | 719.48 (447.06) | -56.45 (-35.08) -7.3% |
255/40-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.57 mph (34.71 km/h) |
| 25 mph (40.23 km/h) | 26.96 mph (43.39 km/h) |
| 30 mph (48.28 km/h) | 32.35 mph (52.07 km/h) |
| 35 mph (56.33 km/h) | 37.75 mph (60.75 km/h) |
| 40 mph (64.37 km/h) | 43.14 mph (69.42 km/h) |
| 45 mph (72.42 km/h) | 48.53 mph (78.1 km/h) |
| 50 mph (80.47 km/h) | 53.92 mph (86.78 km/h) |
| 55 mph (88.51 km/h) | 59.32 mph (95.46 km/h) |
| 60 mph (96.56 km/h) | 64.71 mph (104.14 km/h) |
| 65 mph (104.61 km/h) | 70.1 mph (112.82 km/h) |
| 70 mph (112.65 km/h) | 75.49 mph (121.49 km/h) |
| 75 mph (120.7 km/h) | 80.88 mph (130.17 km/h) |
| 80 mph (128.75 km/h) | 86.28 mph (138.85 km/h) |
| 85 mph (136.79 km/h) | 91.67 mph (147.53 km/h) |
| 90 mph (144.84 km/h) | 97.06 mph (156.21 km/h) |
| 95 mph (152.89 km/h) | 102.45 mph (164.88 km/h) |
| 100 mph (160.93 km/h) | 107.85 mph (173.56 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1831 | 2127 | 2291 | 2392 | 2501 | 2579 | 2665 | 2766 | 2906 | 3046 | 3202 | 3327 | 3553 | 3802 | 3997 | 4122 | 4192 | 4449 | 4807 | 5586 |
Better Fuel Economy Factory Ratios Increased Power
