Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 145/70-18 | 255/45-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 25.99 (660.2) | 29.04 (737.5) | 3.04 (77.3) 11.7% |
| Width inches (mm) | 5.71 (145) | 10.04 (255) | 4.33 (110) 75.9% |
| Circum. inches (mm) | 81.66 (2074.08) | 91.22 (2316.92) | 9.56 (242.85) 11.7% |
| Sidewall Height inches (mm) | 4 (101.5) | 4.52 (114.75) | 0.52 (13.25) 13.1% |
| Revolutions per mile (km) | 775.93 (482.14) | 694.6 (431.61) | -81.33 (-50.53) -10.5% |
255/45-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 22.34 mph (35.96 km/h) |
| 25 mph (40.23 km/h) | 27.93 mph (44.94 km/h) |
| 30 mph (48.28 km/h) | 33.51 mph (53.93 km/h) |
| 35 mph (56.33 km/h) | 39.1 mph (62.92 km/h) |
| 40 mph (64.37 km/h) | 44.68 mph (71.91 km/h) |
| 45 mph (72.42 km/h) | 50.27 mph (80.9 km/h) |
| 50 mph (80.47 km/h) | 55.85 mph (89.89 km/h) |
| 55 mph (88.51 km/h) | 61.44 mph (98.88 km/h) |
| 60 mph (96.56 km/h) | 67.03 mph (107.87 km/h) |
| 65 mph (104.61 km/h) | 72.61 mph (116.86 km/h) |
| 70 mph (112.65 km/h) | 78.2 mph (125.84 km/h) |
| 75 mph (120.7 km/h) | 83.78 mph (134.83 km/h) |
| 80 mph (128.75 km/h) | 89.37 mph (143.82 km/h) |
| 85 mph (136.79 km/h) | 94.95 mph (152.81 km/h) |
| 90 mph (144.84 km/h) | 100.54 mph (161.8 km/h) |
| 95 mph (152.89 km/h) | 106.12 mph (170.79 km/h) |
| 100 mph (160.93 km/h) | 111.71 mph (179.78 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1768 | 2053 | 2211 | 2309 | 2415 | 2490 | 2572 | 2670 | 2806 | 2941 | 3091 | 3212 | 3430 | 3671 | 3859 | 3979 | 4047 | 4295 | 4641 | 5393 |
Better Fuel Economy Factory Ratios Increased Power
