Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 305/25-21 | 305/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27 (685.9) | 28.2 (716.4) | 1.2 (30.5) 4.4% |
| Width inches (mm) | 12.01 (305) | 12.01 (305) | 0 (0) 0% |
| Circum. inches (mm) | 84.84 (2154.82) | 88.61 (2250.64) | 3.77 (95.82) 4.4% |
| Sidewall Height inches (mm) | 3 (76.25) | 3.6 (91.5) | 0.6 (15.25) 20% |
| Revolutions per mile (km) | 746.86 (464.08) | 715.06 (444.32) | -31.8 (-19.76) -4.3% |
305/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.89 mph (33.62 km/h) |
| 25 mph (40.23 km/h) | 26.11 mph (42.02 km/h) |
| 30 mph (48.28 km/h) | 31.33 mph (50.43 km/h) |
| 35 mph (56.33 km/h) | 36.56 mph (58.83 km/h) |
| 40 mph (64.37 km/h) | 41.78 mph (67.24 km/h) |
| 45 mph (72.42 km/h) | 47 mph (75.64 km/h) |
| 50 mph (80.47 km/h) | 52.22 mph (84.05 km/h) |
| 55 mph (88.51 km/h) | 57.45 mph (92.45 km/h) |
| 60 mph (96.56 km/h) | 62.67 mph (100.85 km/h) |
| 65 mph (104.61 km/h) | 67.89 mph (109.26 km/h) |
| 70 mph (112.65 km/h) | 73.11 mph (117.66 km/h) |
| 75 mph (120.7 km/h) | 78.34 mph (126.07 km/h) |
| 80 mph (128.75 km/h) | 83.56 mph (134.47 km/h) |
| 85 mph (136.79 km/h) | 88.78 mph (142.88 km/h) |
| 90 mph (144.84 km/h) | 94 mph (151.28 km/h) |
| 95 mph (152.89 km/h) | 99.22 mph (159.69 km/h) |
| 100 mph (160.93 km/h) | 104.45 mph (168.09 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
