Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/30-21 | 305/30-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.73 (704.4) | 28.2 (716.4) | 0.47 (12) 1.7% |
| Width inches (mm) | 11.22 (285) | 12.01 (305) | 0.79 (20) 7% |
| Circum. inches (mm) | 87.12 (2212.94) | 88.61 (2250.64) | 1.48 (37.7) 1.7% |
| Sidewall Height inches (mm) | 3.37 (85.5) | 3.6 (91.5) | 0.24 (6) 7% |
| Revolutions per mile (km) | 727.24 (451.89) | 715.06 (444.32) | -12.18 (-7.57) -1.7% |
305/30-21 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.34 mph (32.74 km/h) |
| 25 mph (40.23 km/h) | 25.43 mph (40.92 km/h) |
| 30 mph (48.28 km/h) | 30.51 mph (49.1 km/h) |
| 35 mph (56.33 km/h) | 35.6 mph (57.29 km/h) |
| 40 mph (64.37 km/h) | 40.68 mph (65.47 km/h) |
| 45 mph (72.42 km/h) | 45.77 mph (73.65 km/h) |
| 50 mph (80.47 km/h) | 50.85 mph (81.84 km/h) |
| 55 mph (88.51 km/h) | 55.94 mph (90.02 km/h) |
| 60 mph (96.56 km/h) | 61.02 mph (98.21 km/h) |
| 65 mph (104.61 km/h) | 66.11 mph (106.39 km/h) |
| 70 mph (112.65 km/h) | 71.19 mph (114.57 km/h) |
| 75 mph (120.7 km/h) | 76.28 mph (122.76 km/h) |
| 80 mph (128.75 km/h) | 81.36 mph (130.94 km/h) |
| 85 mph (136.79 km/h) | 86.45 mph (139.12 km/h) |
| 90 mph (144.84 km/h) | 91.53 mph (147.31 km/h) |
| 95 mph (152.89 km/h) | 96.62 mph (155.49 km/h) |
| 100 mph (160.93 km/h) | 101.7 mph (163.68 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
