Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/40-18 | 31/18-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.24 (717.2) | 30.95 (786.24) | 2.72 (69.04) 9.6% |
| Width inches (mm) | 12.8 (325) | 17.99 (457) | 5.2 (132) 40.6% |
| Circum. inches (mm) | 88.71 (2253.15) | 97.25 (2470.05) | 8.54 (216.9) 9.6% |
| Sidewall Height inches (mm) | 5.12 (130) | 6.48 (164.52) | 1.36 (34.52) 26.6% |
| Revolutions per mile (km) | 714.26 (443.82) | 651.54 (404.85) | -62.72 (-38.97) -8.8% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.93 mph (35.29 km/h) |
| 25 mph (40.23 km/h) | 27.41 mph (44.11 km/h) |
| 30 mph (48.28 km/h) | 32.89 mph (52.93 km/h) |
| 35 mph (56.33 km/h) | 38.37 mph (61.75 km/h) |
| 40 mph (64.37 km/h) | 43.85 mph (70.57 km/h) |
| 45 mph (72.42 km/h) | 49.33 mph (79.39 km/h) |
| 50 mph (80.47 km/h) | 54.81 mph (88.21 km/h) |
| 55 mph (88.51 km/h) | 60.29 mph (97.03 km/h) |
| 60 mph (96.56 km/h) | 65.78 mph (105.86 km/h) |
| 65 mph (104.61 km/h) | 71.26 mph (114.68 km/h) |
| 70 mph (112.65 km/h) | 76.74 mph (123.5 km/h) |
| 75 mph (120.7 km/h) | 82.22 mph (132.32 km/h) |
| 80 mph (128.75 km/h) | 87.7 mph (141.14 km/h) |
| 85 mph (136.79 km/h) | 93.18 mph (149.96 km/h) |
| 90 mph (144.84 km/h) | 98.66 mph (158.78 km/h) |
| 95 mph (152.89 km/h) | 104.15 mph (167.61 km/h) |
| 100 mph (160.93 km/h) | 109.63 mph (176.43 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1658 | 1926 | 2074 | 2166 | 2265 | 2335 | 2413 | 2505 | 2632 | 2759 | 2900 | 3013 | 3217 | 3443 | 3620 | 3732 | 3796 | 4029 | 4353 | 5059 |
Better Fuel Economy Factory Ratios Increased Power
