Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 120/70-21 | 80/90-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.61 (701.4) | 26.67 (677.4) | -0.94 (-24) -3.4% |
| Width inches (mm) | 4.72 (120) | 3.15 (80) | -1.57 (-40) -33.3% |
| Circum. inches (mm) | 86.75 (2203.51) | 83.78 (2128.11) | -2.97 (-75.4) -3.4% |
| Sidewall Height inches (mm) | 3.31 (84) | 2.83 (72) | -0.47 (-12) -14.3% |
| Revolutions per mile (km) | 730.35 (453.82) | 756.23 (469.9) | 25.88 (16.08) 3.5% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.32 mph (31.09 km/h) |
| 25 mph (40.23 km/h) | 24.14 mph (38.86 km/h) |
| 30 mph (48.28 km/h) | 28.97 mph (46.63 km/h) |
| 35 mph (56.33 km/h) | 33.8 mph (54.4 km/h) |
| 40 mph (64.37 km/h) | 38.63 mph (62.17 km/h) |
| 45 mph (72.42 km/h) | 43.46 mph (69.94 km/h) |
| 50 mph (80.47 km/h) | 48.29 mph (77.71 km/h) |
| 55 mph (88.51 km/h) | 53.12 mph (85.49 km/h) |
| 60 mph (96.56 km/h) | 57.95 mph (93.26 km/h) |
| 65 mph (104.61 km/h) | 62.78 mph (101.03 km/h) |
| 70 mph (112.65 km/h) | 67.6 mph (108.8 km/h) |
| 75 mph (120.7 km/h) | 72.43 mph (116.57 km/h) |
| 80 mph (128.75 km/h) | 77.26 mph (124.34 km/h) |
| 85 mph (136.79 km/h) | 82.09 mph (132.11 km/h) |
| 90 mph (144.84 km/h) | 86.92 mph (139.89 km/h) |
| 95 mph (152.89 km/h) | 91.75 mph (147.66 km/h) |
| 100 mph (160.93 km/h) | 96.58 mph (155.43 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1924 | 2236 | 2408 | 2514 | 2629 | 2711 | 2801 | 2907 | 3055 | 3202 | 3366 | 3497 | 3734 | 3996 | 4201 | 4332 | 4406 | 4676 | 5053 | 5872 |
Better Fuel Economy Factory Ratios Increased Power
