Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 305/25-21 | 405/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27 (685.9) | 30.57 (776.4) | 3.56 (90.5) 13.2% |
| Width inches (mm) | 12.01 (305) | 15.94 (405) | 3.94 (100) 32.8% |
| Circum. inches (mm) | 84.84 (2154.82) | 96.03 (2439.13) | 11.19 (284.31) 13.2% |
| Sidewall Height inches (mm) | 3 (76.25) | 4.78 (121.5) | 1.78 (45.25) 59.3% |
| Revolutions per mile (km) | 746.86 (464.08) | 659.8 (409.98) | -87.06 (-54.09) -11.7% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 22.64 mph (36.43 km/h) |
| 25 mph (40.23 km/h) | 28.3 mph (45.54 km/h) |
| 30 mph (48.28 km/h) | 33.96 mph (54.65 km/h) |
| 35 mph (56.33 km/h) | 39.62 mph (63.76 km/h) |
| 40 mph (64.37 km/h) | 45.28 mph (72.87 km/h) |
| 45 mph (72.42 km/h) | 50.94 mph (81.98 km/h) |
| 50 mph (80.47 km/h) | 56.6 mph (91.08 km/h) |
| 55 mph (88.51 km/h) | 62.26 mph (100.19 km/h) |
| 60 mph (96.56 km/h) | 67.92 mph (109.3 km/h) |
| 65 mph (104.61 km/h) | 73.58 mph (118.41 km/h) |
| 70 mph (112.65 km/h) | 79.24 mph (127.52 km/h) |
| 75 mph (120.7 km/h) | 84.9 mph (136.63 km/h) |
| 80 mph (128.75 km/h) | 90.56 mph (145.74 km/h) |
| 85 mph (136.79 km/h) | 96.22 mph (154.84 km/h) |
| 90 mph (144.84 km/h) | 101.87 mph (163.95 km/h) |
| 95 mph (152.89 km/h) | 107.53 mph (173.06 km/h) |
| 100 mph (160.93 km/h) | 113.19 mph (182.17 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1679 | 1951 | 2101 | 2194 | 2294 | 2365 | 2444 | 2536 | 2665 | 2794 | 2937 | 3051 | 3258 | 3487 | 3665 | 3780 | 3844 | 4080 | 4408 | 5123 |
Better Fuel Economy Factory Ratios Increased Power
