Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 120/70-21 | 90/70-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.61 (701.4) | 25.96 (659.4) | -1.65 (-42) -6% |
| Width inches (mm) | 4.72 (120) | 3.54 (90) | -1.18 (-30) -25% |
| Circum. inches (mm) | 86.75 (2203.51) | 81.56 (2071.57) | -5.19 (-131.95) -6% |
| Sidewall Height inches (mm) | 3.31 (84) | 2.48 (63) | -0.83 (-21) -25% |
| Revolutions per mile (km) | 730.35 (453.82) | 776.87 (482.73) | 46.52 (28.91) 6.4% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 18.8 mph (30.26 km/h) |
| 25 mph (40.23 km/h) | 23.5 mph (37.82 km/h) |
| 30 mph (48.28 km/h) | 28.2 mph (45.39 km/h) |
| 35 mph (56.33 km/h) | 32.9 mph (52.95 km/h) |
| 40 mph (64.37 km/h) | 37.6 mph (60.52 km/h) |
| 45 mph (72.42 km/h) | 42.31 mph (68.08 km/h) |
| 50 mph (80.47 km/h) | 47.01 mph (75.65 km/h) |
| 55 mph (88.51 km/h) | 51.71 mph (83.21 km/h) |
| 60 mph (96.56 km/h) | 56.41 mph (90.78 km/h) |
| 65 mph (104.61 km/h) | 61.11 mph (98.34 km/h) |
| 70 mph (112.65 km/h) | 65.81 mph (105.91 km/h) |
| 75 mph (120.7 km/h) | 70.51 mph (113.47 km/h) |
| 80 mph (128.75 km/h) | 75.21 mph (121.04 km/h) |
| 85 mph (136.79 km/h) | 79.91 mph (128.6 km/h) |
| 90 mph (144.84 km/h) | 84.61 mph (136.17 km/h) |
| 95 mph (152.89 km/h) | 89.31 mph (143.73 km/h) |
| 100 mph (160.93 km/h) | 94.01 mph (151.3 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1977 | 2297 | 2473 | 2583 | 2700 | 2785 | 2877 | 2987 | 3138 | 3289 | 3458 | 3592 | 3836 | 4105 | 4316 | 4450 | 4526 | 4804 | 5191 | 6032 |
Better Fuel Economy Factory Ratios Increased Power
