Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 38/15.5-20 | 40/13.5-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 37.99 (965.04) | 39.99 (1015.64) | 1.99 (50.6) 5.2% |
| Width inches (mm) | 15.51 (394) | 13.5 (343) | -2.01 (-51) -12.9% |
| Circum. inches (mm) | 119.36 (3031.76) | 125.62 (3190.73) | 6.26 (158.96) 5.2% |
| Sidewall Height inches (mm) | 9 (228.52) | 9.99 (253.82) | 1 (25.3) 11.1% |
| Revolutions per mile (km) | 530.83 (329.84) | 504.38 (313.41) | -26.45 (-16.43) -5% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.05 mph (33.87 km/h) |
| 25 mph (40.23 km/h) | 26.31 mph (42.34 km/h) |
| 30 mph (48.28 km/h) | 31.57 mph (50.81 km/h) |
| 35 mph (56.33 km/h) | 36.84 mph (59.28 km/h) |
| 40 mph (64.37 km/h) | 42.1 mph (67.75 km/h) |
| 45 mph (72.42 km/h) | 47.36 mph (76.22 km/h) |
| 50 mph (80.47 km/h) | 52.62 mph (84.69 km/h) |
| 55 mph (88.51 km/h) | 57.88 mph (93.16 km/h) |
| 60 mph (96.56 km/h) | 63.15 mph (101.62 km/h) |
| 65 mph (104.61 km/h) | 68.41 mph (110.09 km/h) |
| 70 mph (112.65 km/h) | 73.67 mph (118.56 km/h) |
| 75 mph (120.7 km/h) | 78.93 mph (127.03 km/h) |
| 80 mph (128.75 km/h) | 84.19 mph (135.5 km/h) |
| 85 mph (136.79 km/h) | 89.46 mph (143.97 km/h) |
| 90 mph (144.84 km/h) | 94.72 mph (152.44 km/h) |
| 95 mph (152.89 km/h) | 99.98 mph (160.9 km/h) |
| 100 mph (160.93 km/h) | 105.24 mph (169.37 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1284 | 1491 | 1606 | 1677 | 1753 | 1808 | 1868 | 1939 | 2037 | 2136 | 2245 | 2332 | 2491 | 2665 | 2802 | 2889 | 2939 | 3119 | 3370 | 3916 |
Better Fuel Economy Factory Ratios Increased Power
