Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 325/25-21 | 255/30-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.4 (695.9) | 26.02 (661) | -1.37 (-34.9) -5% |
| Width inches (mm) | 12.8 (325) | 10.04 (255) | -2.76 (-70) -21.5% |
| Circum. inches (mm) | 86.07 (2186.23) | 81.76 (2076.59) | -4.32 (-109.64) -5% |
| Sidewall Height inches (mm) | 3.2 (81.25) | 3.01 (76.5) | -0.19 (-4.75) -5.8% |
| Revolutions per mile (km) | 736.13 (457.41) | 774.99 (481.56) | 38.87 (24.15) 5.3% |
255/30-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19 mph (30.57 km/h) |
| 25 mph (40.23 km/h) | 23.75 mph (38.22 km/h) |
| 30 mph (48.28 km/h) | 28.5 mph (45.86 km/h) |
| 35 mph (56.33 km/h) | 33.24 mph (53.5 km/h) |
| 40 mph (64.37 km/h) | 37.99 mph (61.15 km/h) |
| 45 mph (72.42 km/h) | 42.74 mph (68.79 km/h) |
| 50 mph (80.47 km/h) | 47.49 mph (76.43 km/h) |
| 55 mph (88.51 km/h) | 52.24 mph (84.08 km/h) |
| 60 mph (96.56 km/h) | 56.99 mph (91.72 km/h) |
| 65 mph (104.61 km/h) | 61.74 mph (99.36 km/h) |
| 70 mph (112.65 km/h) | 66.49 mph (107 km/h) |
| 75 mph (120.7 km/h) | 71.24 mph (114.65 km/h) |
| 80 mph (128.75 km/h) | 75.99 mph (122.29 km/h) |
| 85 mph (136.79 km/h) | 80.74 mph (129.93 km/h) |
| 90 mph (144.84 km/h) | 85.49 mph (137.58 km/h) |
| 95 mph (152.89 km/h) | 90.24 mph (145.22 km/h) |
| 100 mph (160.93 km/h) | 94.98 mph (152.86 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1972 | 2291 | 2467 | 2576 | 2694 | 2778 | 2870 | 2979 | 3130 | 3281 | 3449 | 3584 | 3827 | 4095 | 4305 | 4440 | 4515 | 4792 | 5178 | 6017 |
Better Fuel Economy Factory Ratios Increased Power
