Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 120/70-21 | 120/90-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.61 (701.4) | 29.5 (749.4) | 1.89 (48) 6.8% |
| Width inches (mm) | 4.72 (120) | 4.72 (120) | 0 (0) 0% |
| Circum. inches (mm) | 86.75 (2203.51) | 92.69 (2354.31) | 5.94 (150.8) 6.8% |
| Sidewall Height inches (mm) | 3.31 (84) | 4.25 (108) | 0.94 (24) 28.6% |
| Revolutions per mile (km) | 730.35 (453.82) | 683.57 (424.75) | -46.78 (-29.07) -6.4% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.37 mph (34.39 km/h) |
| 25 mph (40.23 km/h) | 26.71 mph (42.99 km/h) |
| 30 mph (48.28 km/h) | 32.05 mph (51.58 km/h) |
| 35 mph (56.33 km/h) | 37.4 mph (60.18 km/h) |
| 40 mph (64.37 km/h) | 42.74 mph (68.78 km/h) |
| 45 mph (72.42 km/h) | 48.08 mph (77.38 km/h) |
| 50 mph (80.47 km/h) | 53.42 mph (85.97 km/h) |
| 55 mph (88.51 km/h) | 58.76 mph (94.57 km/h) |
| 60 mph (96.56 km/h) | 64.11 mph (103.17 km/h) |
| 65 mph (104.61 km/h) | 69.45 mph (111.77 km/h) |
| 70 mph (112.65 km/h) | 74.79 mph (120.36 km/h) |
| 75 mph (120.7 km/h) | 80.13 mph (128.96 km/h) |
| 80 mph (128.75 km/h) | 85.47 mph (137.56 km/h) |
| 85 mph (136.79 km/h) | 90.82 mph (146.16 km/h) |
| 90 mph (144.84 km/h) | 96.16 mph (154.75 km/h) |
| 95 mph (152.89 km/h) | 101.5 mph (163.35 km/h) |
| 100 mph (160.93 km/h) | 106.84 mph (171.95 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1740 | 2021 | 2176 | 2273 | 2376 | 2450 | 2532 | 2628 | 2761 | 2894 | 3042 | 3161 | 3375 | 3612 | 3797 | 3916 | 3982 | 4227 | 4567 | 5308 |
Better Fuel Economy Factory Ratios Increased Power
