Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 38/15.5-20 | 42/14.5-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 37.99 (965.04) | 42.02 (1067.36) | 4.03 (102.32) 10.6% |
| Width inches (mm) | 15.51 (394) | 14.49 (368) | -1.02 (-26) -6.6% |
| Circum. inches (mm) | 119.36 (3031.76) | 132.02 (3353.21) | 12.66 (321.45) 10.6% |
| Sidewall Height inches (mm) | 9 (228.52) | 11.01 (279.68) | 2.01 (51.16) 22.4% |
| Revolutions per mile (km) | 530.83 (329.84) | 479.94 (298.22) | -50.89 (-31.62) -9.6% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 22.12 mph (35.6 km/h) |
| 25 mph (40.23 km/h) | 27.65 mph (44.5 km/h) |
| 30 mph (48.28 km/h) | 33.18 mph (53.4 km/h) |
| 35 mph (56.33 km/h) | 38.71 mph (62.3 km/h) |
| 40 mph (64.37 km/h) | 44.24 mph (71.2 km/h) |
| 45 mph (72.42 km/h) | 49.77 mph (80.1 km/h) |
| 50 mph (80.47 km/h) | 55.3 mph (89 km/h) |
| 55 mph (88.51 km/h) | 60.83 mph (97.9 km/h) |
| 60 mph (96.56 km/h) | 66.36 mph (106.8 km/h) |
| 65 mph (104.61 km/h) | 71.89 mph (115.7 km/h) |
| 70 mph (112.65 km/h) | 77.42 mph (124.6 km/h) |
| 75 mph (120.7 km/h) | 82.95 mph (133.5 km/h) |
| 80 mph (128.75 km/h) | 88.48 mph (142.4 km/h) |
| 85 mph (136.79 km/h) | 94.01 mph (151.3 km/h) |
| 90 mph (144.84 km/h) | 99.54 mph (160.2 km/h) |
| 95 mph (152.89 km/h) | 105.07 mph (169.1 km/h) |
| 100 mph (160.93 km/h) | 110.6 mph (178 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1221 | 1419 | 1528 | 1596 | 1668 | 1720 | 1777 | 1845 | 1939 | 2032 | 2136 | 2219 | 2370 | 2536 | 2666 | 2749 | 2796 | 2968 | 3207 | 3726 |
Better Fuel Economy Factory Ratios Increased Power
