Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 38/13.5-20 | 40/15.5-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 38.1 (967.62) | 40.17 (1020.2) | 2.07 (52.58) 5.4% |
| Width inches (mm) | 13.5 (343) | 15.51 (394) | 2.01 (51) 14.9% |
| Circum. inches (mm) | 119.68 (3039.87) | 126.18 (3205.05) | 6.5 (165.18) 5.4% |
| Sidewall Height inches (mm) | 9.05 (229.81) | 10.08 (256.1) | 1.04 (26.29) 11.4% |
| Revolutions per mile (km) | 529.41 (328.96) | 502.13 (312.01) | -27.29 (-16.95) -5.2% |
40/15.5-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.09 mph (33.94 km/h) |
| 25 mph (40.23 km/h) | 26.36 mph (42.42 km/h) |
| 30 mph (48.28 km/h) | 31.63 mph (50.9 km/h) |
| 35 mph (56.33 km/h) | 36.9 mph (59.39 km/h) |
| 40 mph (64.37 km/h) | 42.17 mph (67.87 km/h) |
| 45 mph (72.42 km/h) | 47.45 mph (76.36 km/h) |
| 50 mph (80.47 km/h) | 52.72 mph (84.84 km/h) |
| 55 mph (88.51 km/h) | 57.99 mph (93.32 km/h) |
| 60 mph (96.56 km/h) | 63.26 mph (101.81 km/h) |
| 65 mph (104.61 km/h) | 68.53 mph (110.29 km/h) |
| 70 mph (112.65 km/h) | 73.8 mph (118.78 km/h) |
| 75 mph (120.7 km/h) | 79.08 mph (127.26 km/h) |
| 80 mph (128.75 km/h) | 84.35 mph (135.74 km/h) |
| 85 mph (136.79 km/h) | 89.62 mph (144.23 km/h) |
| 90 mph (144.84 km/h) | 94.89 mph (152.71 km/h) |
| 95 mph (152.89 km/h) | 100.16 mph (161.2 km/h) |
| 100 mph (160.93 km/h) | 105.43 mph (169.68 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1278 | 1484 | 1599 | 1669 | 1745 | 1800 | 1860 | 1930 | 2028 | 2126 | 2235 | 2322 | 2480 | 2654 | 2789 | 2876 | 2925 | 3105 | 3355 | 3899 |
Better Fuel Economy Factory Ratios Increased Power
