Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 305/30-21 | 315/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.2 (716.4) | 28.44 (722.4) | 0.24 (6) 0.8% |
| Width inches (mm) | 12.01 (305) | 12.4 (315) | 0.39 (10) 3.3% |
| Circum. inches (mm) | 88.61 (2250.64) | 89.35 (2269.49) | 0.74 (18.85) 0.8% |
| Sidewall Height inches (mm) | 3.6 (91.5) | 3.72 (94.5) | 0.12 (3) 3.3% |
| Revolutions per mile (km) | 715.06 (444.32) | 709.12 (440.63) | -5.94 (-3.69) -0.8% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.17 mph (32.46 km/h) |
| 25 mph (40.23 km/h) | 25.21 mph (40.57 km/h) |
| 30 mph (48.28 km/h) | 30.25 mph (48.68 km/h) |
| 35 mph (56.33 km/h) | 35.29 mph (56.8 km/h) |
| 40 mph (64.37 km/h) | 40.34 mph (64.91 km/h) |
| 45 mph (72.42 km/h) | 45.38 mph (73.03 km/h) |
| 50 mph (80.47 km/h) | 50.42 mph (81.14 km/h) |
| 55 mph (88.51 km/h) | 55.46 mph (89.26 km/h) |
| 60 mph (96.56 km/h) | 60.5 mph (97.37 km/h) |
| 65 mph (104.61 km/h) | 65.54 mph (105.48 km/h) |
| 70 mph (112.65 km/h) | 70.59 mph (113.6 km/h) |
| 75 mph (120.7 km/h) | 75.63 mph (121.71 km/h) |
| 80 mph (128.75 km/h) | 80.67 mph (129.83 km/h) |
| 85 mph (136.79 km/h) | 85.71 mph (137.94 km/h) |
| 90 mph (144.84 km/h) | 90.75 mph (146.05 km/h) |
| 95 mph (152.89 km/h) | 95.8 mph (154.17 km/h) |
| 100 mph (160.93 km/h) | 100.84 mph (162.28 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
