Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/30-21 | 325/40-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.68 (728.4) | 31.24 (793.4) | 2.56 (65) 8.9% |
| Width inches (mm) | 12.8 (325) | 12.8 (325) | 0 (0) 0% |
| Circum. inches (mm) | 90.09 (2288.34) | 98.13 (2492.54) | 8.04 (204.2) 8.9% |
| Sidewall Height inches (mm) | 3.84 (97.5) | 5.12 (130) | 1.28 (32.5) 33.3% |
| Revolutions per mile (km) | 703.28 (437) | 645.66 (401.2) | -57.62 (-35.8) -8.2% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.78 mph (35.06 km/h) |
| 25 mph (40.23 km/h) | 27.23 mph (43.82 km/h) |
| 30 mph (48.28 km/h) | 32.68 mph (52.59 km/h) |
| 35 mph (56.33 km/h) | 38.12 mph (61.35 km/h) |
| 40 mph (64.37 km/h) | 43.57 mph (70.12 km/h) |
| 45 mph (72.42 km/h) | 49.02 mph (78.88 km/h) |
| 50 mph (80.47 km/h) | 54.46 mph (87.65 km/h) |
| 55 mph (88.51 km/h) | 59.91 mph (96.41 km/h) |
| 60 mph (96.56 km/h) | 65.35 mph (105.18 km/h) |
| 65 mph (104.61 km/h) | 70.8 mph (113.94 km/h) |
| 70 mph (112.65 km/h) | 76.25 mph (122.71 km/h) |
| 75 mph (120.7 km/h) | 81.69 mph (131.47 km/h) |
| 80 mph (128.75 km/h) | 87.14 mph (140.24 km/h) |
| 85 mph (136.79 km/h) | 92.59 mph (149 km/h) |
| 90 mph (144.84 km/h) | 98.03 mph (157.77 km/h) |
| 95 mph (152.89 km/h) | 103.48 mph (166.53 km/h) |
| 100 mph (160.93 km/h) | 108.92 mph (175.3 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1643 | 1909 | 2056 | 2147 | 2244 | 2314 | 2391 | 2482 | 2608 | 2734 | 2874 | 2986 | 3188 | 3412 | 3587 | 3699 | 3762 | 3992 | 4314 | 5013 |
Better Fuel Economy Factory Ratios Increased Power
