Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/25-21 | 315/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.4 (695.9) | 28.44 (722.4) | 1.04 (26.5) 3.8% |
| Width inches (mm) | 12.8 (325) | 12.4 (315) | -0.39 (-10) -3.1% |
| Circum. inches (mm) | 86.07 (2186.23) | 89.35 (2269.49) | 3.28 (83.25) 3.8% |
| Sidewall Height inches (mm) | 3.2 (81.25) | 3.72 (94.5) | 0.52 (13.25) 16.3% |
| Revolutions per mile (km) | 736.13 (457.41) | 709.12 (440.63) | -27 (-16.78) -3.7% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.76 mph (33.41 km/h) |
| 25 mph (40.23 km/h) | 25.95 mph (41.77 km/h) |
| 30 mph (48.28 km/h) | 31.14 mph (50.12 km/h) |
| 35 mph (56.33 km/h) | 36.33 mph (58.47 km/h) |
| 40 mph (64.37 km/h) | 41.52 mph (66.83 km/h) |
| 45 mph (72.42 km/h) | 46.71 mph (75.18 km/h) |
| 50 mph (80.47 km/h) | 51.9 mph (83.53 km/h) |
| 55 mph (88.51 km/h) | 57.09 mph (91.88 km/h) |
| 60 mph (96.56 km/h) | 62.28 mph (100.24 km/h) |
| 65 mph (104.61 km/h) | 67.48 mph (108.59 km/h) |
| 70 mph (112.65 km/h) | 72.67 mph (116.94 km/h) |
| 75 mph (120.7 km/h) | 77.86 mph (125.3 km/h) |
| 80 mph (128.75 km/h) | 83.05 mph (133.65 km/h) |
| 85 mph (136.79 km/h) | 88.24 mph (142 km/h) |
| 90 mph (144.84 km/h) | 93.43 mph (150.36 km/h) |
| 95 mph (152.89 km/h) | 98.62 mph (158.71 km/h) |
| 100 mph (160.93 km/h) | 103.81 mph (167.06 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1805 | 2096 | 2258 | 2357 | 2465 | 2542 | 2626 | 2726 | 2864 | 3003 | 3156 | 3279 | 3502 | 3747 | 3939 | 4062 | 4131 | 4385 | 4738 | 5506 |
Better Fuel Economy Factory Ratios Increased Power
