Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 40/12.5-20 | 38/12.5-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 40.03 (1016.8) | 38.03 (965.92) | -2 (-50.88) -5% |
| Width inches (mm) | 12.52 (318) | 12.52 (318) | 0 (0) 0% |
| Circum. inches (mm) | 125.76 (3194.37) | 119.47 (3034.53) | -6.29 (-159.84) -5% |
| Sidewall Height inches (mm) | 10.02 (254.4) | 9.01 (228.96) | -1 (-25.44) -10% |
| Revolutions per mile (km) | 503.81 (313.05) | 530.34 (329.54) | 26.54 (16.49) 5.3% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19 mph (30.58 km/h) |
| 25 mph (40.23 km/h) | 23.75 mph (38.22 km/h) |
| 30 mph (48.28 km/h) | 28.5 mph (45.86 km/h) |
| 35 mph (56.33 km/h) | 33.25 mph (53.51 km/h) |
| 40 mph (64.37 km/h) | 38 mph (61.15 km/h) |
| 45 mph (72.42 km/h) | 42.75 mph (68.8 km/h) |
| 50 mph (80.47 km/h) | 47.5 mph (76.44 km/h) |
| 55 mph (88.51 km/h) | 52.25 mph (84.08 km/h) |
| 60 mph (96.56 km/h) | 57 mph (91.73 km/h) |
| 65 mph (104.61 km/h) | 61.75 mph (99.37 km/h) |
| 70 mph (112.65 km/h) | 66.5 mph (107.02 km/h) |
| 75 mph (120.7 km/h) | 71.25 mph (114.66 km/h) |
| 80 mph (128.75 km/h) | 76 mph (122.31 km/h) |
| 85 mph (136.79 km/h) | 80.75 mph (129.95 km/h) |
| 90 mph (144.84 km/h) | 85.5 mph (137.59 km/h) |
| 95 mph (152.89 km/h) | 90.25 mph (145.24 km/h) |
| 100 mph (160.93 km/h) | 95 mph (152.88 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1350 | 1568 | 1688 | 1763 | 1844 | 1901 | 1964 | 2039 | 2142 | 2246 | 2360 | 2452 | 2619 | 2803 | 2946 | 3038 | 3090 | 3279 | 3543 | 4118 |
Better Fuel Economy Factory Ratios Increased Power
