Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/30-21 | 305/30-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.68 (728.4) | 27.2 (691) | -1.47 (-37.4) -5.1% |
| Width inches (mm) | 12.8 (325) | 12.01 (305) | -0.79 (-20) -6.2% |
| Circum. inches (mm) | 90.09 (2288.34) | 85.47 (2170.84) | -4.63 (-117.5) -5.1% |
| Sidewall Height inches (mm) | 3.84 (97.5) | 3.6 (91.5) | -0.24 (-6) -6.2% |
| Revolutions per mile (km) | 703.28 (437) | 741.35 (460.65) | 38.06 (23.65) 5.4% |
305/30-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 18.97 mph (30.53 km/h) |
| 25 mph (40.23 km/h) | 23.72 mph (38.17 km/h) |
| 30 mph (48.28 km/h) | 28.46 mph (45.8 km/h) |
| 35 mph (56.33 km/h) | 33.2 mph (53.44 km/h) |
| 40 mph (64.37 km/h) | 37.95 mph (61.07 km/h) |
| 45 mph (72.42 km/h) | 42.69 mph (68.7 km/h) |
| 50 mph (80.47 km/h) | 47.43 mph (76.34 km/h) |
| 55 mph (88.51 km/h) | 52.18 mph (83.97 km/h) |
| 60 mph (96.56 km/h) | 56.92 mph (91.6 km/h) |
| 65 mph (104.61 km/h) | 61.66 mph (99.24 km/h) |
| 70 mph (112.65 km/h) | 66.41 mph (106.87 km/h) |
| 75 mph (120.7 km/h) | 71.15 mph (114.5 km/h) |
| 80 mph (128.75 km/h) | 75.89 mph (122.14 km/h) |
| 85 mph (136.79 km/h) | 80.64 mph (129.77 km/h) |
| 90 mph (144.84 km/h) | 85.38 mph (137.4 km/h) |
| 95 mph (152.89 km/h) | 90.12 mph (145.04 km/h) |
| 100 mph (160.93 km/h) | 94.87 mph (152.67 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1887 | 2192 | 2360 | 2465 | 2577 | 2657 | 2746 | 2850 | 2994 | 3139 | 3300 | 3428 | 3661 | 3918 | 4118 | 4247 | 4319 | 4584 | 4953 | 5756 |
Better Fuel Economy Factory Ratios Increased Power
