Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/30-21 | 305/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.68 (728.4) | 28.2 (716.4) | -0.47 (-12) -1.6% |
| Width inches (mm) | 12.8 (325) | 12.01 (305) | -0.79 (-20) -6.2% |
| Circum. inches (mm) | 90.09 (2288.34) | 88.61 (2250.64) | -1.48 (-37.7) -1.6% |
| Sidewall Height inches (mm) | 3.84 (97.5) | 3.6 (91.5) | -0.24 (-6) -6.2% |
| Revolutions per mile (km) | 703.28 (437) | 715.06 (444.32) | 11.78 (7.32) 1.7% |
305/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.67 mph (31.66 km/h) |
| 25 mph (40.23 km/h) | 24.59 mph (39.57 km/h) |
| 30 mph (48.28 km/h) | 29.51 mph (47.49 km/h) |
| 35 mph (56.33 km/h) | 34.42 mph (55.4 km/h) |
| 40 mph (64.37 km/h) | 39.34 mph (63.31 km/h) |
| 45 mph (72.42 km/h) | 44.26 mph (71.23 km/h) |
| 50 mph (80.47 km/h) | 49.18 mph (79.14 km/h) |
| 55 mph (88.51 km/h) | 54.09 mph (87.06 km/h) |
| 60 mph (96.56 km/h) | 59.01 mph (94.97 km/h) |
| 65 mph (104.61 km/h) | 63.93 mph (102.88 km/h) |
| 70 mph (112.65 km/h) | 68.85 mph (110.8 km/h) |
| 75 mph (120.7 km/h) | 73.76 mph (118.71 km/h) |
| 80 mph (128.75 km/h) | 78.68 mph (126.63 km/h) |
| 85 mph (136.79 km/h) | 83.6 mph (134.54 km/h) |
| 90 mph (144.84 km/h) | 88.52 mph (142.46 km/h) |
| 95 mph (152.89 km/h) | 93.43 mph (150.37 km/h) |
| 100 mph (160.93 km/h) | 98.35 mph (158.28 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1820 | 2114 | 2277 | 2377 | 2486 | 2563 | 2648 | 2749 | 2888 | 3028 | 3183 | 3306 | 3531 | 3779 | 3972 | 4096 | 4166 | 4421 | 4778 | 5552 |
Better Fuel Economy Factory Ratios Increased Power
