Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/30-21 | 325/40-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.68 (728.4) | 30.24 (768) | 1.56 (39.6) 5.4% |
| Width inches (mm) | 12.8 (325) | 12.8 (325) | 0 (0) 0% |
| Circum. inches (mm) | 90.09 (2288.34) | 94.99 (2412.74) | 4.9 (124.41) 5.4% |
| Sidewall Height inches (mm) | 3.84 (97.5) | 5.12 (130) | 1.28 (32.5) 33.3% |
| Revolutions per mile (km) | 703.28 (437) | 667.02 (414.47) | -36.26 (-22.53) -5.2% |
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 (50.91 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 (93.33 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) | 73.81 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 (135.75 km/h) |
| 85 mph (136.79 km/h) | 89.62 mph (144.23 km/h) |
| 90 mph (144.84 km/h) | 94.89 mph (152.72 km/h) |
| 95 mph (152.89 km/h) | 100.16 mph (161.2 km/h) |
| 100 mph (160.93 km/h) | 105.44 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1697 | 1972 | 2124 | 2217 | 2319 | 2391 | 2470 | 2564 | 2694 | 2824 | 2969 | 3084 | 3294 | 3525 | 3705 | 3821 | 3886 | 4124 | 4457 | 5179 |
Better Fuel Economy Factory Ratios Increased Power
