Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 40/12.5-20 | 305/75-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 40.03 (1016.8) | 38.01 (965.5) | -2.02 (-51.3) -5% |
| Width inches (mm) | 12.52 (318) | 12.01 (305) | -0.51 (-13) -4.1% |
| Circum. inches (mm) | 125.76 (3194.37) | 119.42 (3033.21) | -6.35 (-161.16) -5% |
| Sidewall Height inches (mm) | 10.02 (254.4) | 9.01 (228.75) | -1.01 (-25.65) -10.1% |
| Revolutions per mile (km) | 503.81 (313.05) | 530.57 (329.68) | 26.77 (16.63) 5.3% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 18.99 mph (30.56 km/h) |
| 25 mph (40.23 km/h) | 23.74 mph (38.2 km/h) |
| 30 mph (48.28 km/h) | 28.49 mph (45.84 km/h) |
| 35 mph (56.33 km/h) | 33.23 mph (53.49 km/h) |
| 40 mph (64.37 km/h) | 37.98 mph (61.13 km/h) |
| 45 mph (72.42 km/h) | 42.73 mph (68.77 km/h) |
| 50 mph (80.47 km/h) | 47.48 mph (76.41 km/h) |
| 55 mph (88.51 km/h) | 52.23 mph (84.05 km/h) |
| 60 mph (96.56 km/h) | 56.97 mph (91.69 km/h) |
| 65 mph (104.61 km/h) | 61.72 mph (99.33 km/h) |
| 70 mph (112.65 km/h) | 66.47 mph (106.97 km/h) |
| 75 mph (120.7 km/h) | 71.22 mph (114.61 km/h) |
| 80 mph (128.75 km/h) | 75.96 mph (122.25 km/h) |
| 85 mph (136.79 km/h) | 80.71 mph (129.89 km/h) |
| 90 mph (144.84 km/h) | 85.46 mph (137.53 km/h) |
| 95 mph (152.89 km/h) | 90.21 mph (145.17 km/h) |
| 100 mph (160.93 km/h) | 94.95 mph (152.82 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 | 1569 | 1689 | 1764 | 1844 | 1902 | 1965 | 2040 | 2143 | 2247 | 2361 | 2453 | 2620 | 2804 | 2947 | 3039 | 3091 | 3281 | 3545 | 4120 |
Better Fuel Economy Factory Ratios Increased Power
