Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 245/30-21 | 305/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 26.79 (680.4) | 28.2 (716.4) | 1.42 (36) 5.3% |
| Width inches (mm) | 9.65 (245) | 12.01 (305) | 2.36 (60) 24.5% |
| Circum. inches (mm) | 84.16 (2137.54) | 88.61 (2250.64) | 4.45 (113.1) 5.3% |
| Sidewall Height inches (mm) | 2.89 (73.5) | 3.6 (91.5) | 0.71 (18) 24.5% |
| Revolutions per mile (km) | 752.9 (467.83) | 715.06 (444.32) | -37.83 (-23.51) -5% |
305/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.06 mph (33.89 km/h) |
| 25 mph (40.23 km/h) | 26.32 mph (42.36 km/h) |
| 30 mph (48.28 km/h) | 31.59 mph (50.83 km/h) |
| 35 mph (56.33 km/h) | 36.85 mph (59.31 km/h) |
| 40 mph (64.37 km/h) | 42.12 mph (67.78 km/h) |
| 45 mph (72.42 km/h) | 47.38 mph (76.25 km/h) |
| 50 mph (80.47 km/h) | 52.65 mph (84.72 km/h) |
| 55 mph (88.51 km/h) | 57.91 mph (93.2 km/h) |
| 60 mph (96.56 km/h) | 63.17 mph (101.67 km/h) |
| 65 mph (104.61 km/h) | 68.44 mph (110.14 km/h) |
| 70 mph (112.65 km/h) | 73.7 mph (118.61 km/h) |
| 75 mph (120.7 km/h) | 78.97 mph (127.09 km/h) |
| 80 mph (128.75 km/h) | 84.23 mph (135.56 km/h) |
| 85 mph (136.79 km/h) | 89.5 mph (144.03 km/h) |
| 90 mph (144.84 km/h) | 94.76 mph (152.5 km/h) |
| 95 mph (152.89 km/h) | 100.03 mph (160.98 km/h) |
| 100 mph (160.93 km/h) | 105.29 mph (169.45 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
