Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/40-18 | 325/30-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.24 (717.2) | 27.68 (703) | -0.56 (-14.2) -2% |
| Width inches (mm) | 12.8 (325) | 12.8 (325) | 0 (0) 0% |
| Circum. inches (mm) | 88.71 (2253.15) | 86.95 (2208.54) | -1.76 (-44.61) -2% |
| Sidewall Height inches (mm) | 5.12 (130) | 3.84 (97.5) | -1.28 (-32.5) -25% |
| Revolutions per mile (km) | 714.26 (443.82) | 728.69 (452.79) | 14.43 (8.96) 2% |
325/30-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.6 mph (31.55 km/h) |
| 25 mph (40.23 km/h) | 24.51 mph (39.44 km/h) |
| 30 mph (48.28 km/h) | 29.41 mph (47.32 km/h) |
| 35 mph (56.33 km/h) | 34.31 mph (55.21 km/h) |
| 40 mph (64.37 km/h) | 39.21 mph (63.1 km/h) |
| 45 mph (72.42 km/h) | 44.11 mph (70.99 km/h) |
| 50 mph (80.47 km/h) | 49.01 mph (78.87 km/h) |
| 55 mph (88.51 km/h) | 53.91 mph (86.76 km/h) |
| 60 mph (96.56 km/h) | 58.81 mph (94.65 km/h) |
| 65 mph (104.61 km/h) | 63.71 mph (102.54 km/h) |
| 70 mph (112.65 km/h) | 68.61 mph (110.42 km/h) |
| 75 mph (120.7 km/h) | 73.52 mph (118.31 km/h) |
| 80 mph (128.75 km/h) | 78.42 mph (126.2 km/h) |
| 85 mph (136.79 km/h) | 83.32 mph (134.09 km/h) |
| 90 mph (144.84 km/h) | 88.22 mph (141.97 km/h) |
| 95 mph (152.89 km/h) | 93.12 mph (149.86 km/h) |
| 100 mph (160.93 km/h) | 98.02 mph (157.75 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1854 | 2154 | 2320 | 2423 | 2533 | 2612 | 2699 | 2801 | 2943 | 3085 | 3243 | 3369 | 3598 | 3851 | 4048 | 4174 | 4245 | 4506 | 4869 | 5658 |
Better Fuel Economy Factory Ratios Increased Power
