Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 120/70-21 | 120/100-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.61 (701.4) | 30.45 (773.4) | 2.83 (72) 10.3% |
| Width inches (mm) | 4.72 (120) | 4.72 (120) | 0 (0) 0% |
| Circum. inches (mm) | 86.75 (2203.51) | 95.66 (2429.71) | 8.91 (226.19) 10.3% |
| Sidewall Height inches (mm) | 3.31 (84) | 4.72 (120) | 1.42 (36) 42.9% |
| Revolutions per mile (km) | 730.35 (453.82) | 662.36 (411.57) | -67.99 (-42.25) -9.3% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 22.05 mph (35.49 km/h) |
| 25 mph (40.23 km/h) | 27.57 mph (44.36 km/h) |
| 30 mph (48.28 km/h) | 33.08 mph (53.24 km/h) |
| 35 mph (56.33 km/h) | 38.59 mph (62.11 km/h) |
| 40 mph (64.37 km/h) | 44.11 mph (70.98 km/h) |
| 45 mph (72.42 km/h) | 49.62 mph (79.85 km/h) |
| 50 mph (80.47 km/h) | 55.13 mph (88.73 km/h) |
| 55 mph (88.51 km/h) | 60.65 mph (97.6 km/h) |
| 60 mph (96.56 km/h) | 66.16 mph (106.47 km/h) |
| 65 mph (104.61 km/h) | 71.67 mph (115.35 km/h) |
| 70 mph (112.65 km/h) | 77.19 mph (124.22 km/h) |
| 75 mph (120.7 km/h) | 82.7 mph (133.09 km/h) |
| 80 mph (128.75 km/h) | 88.21 mph (141.96 km/h) |
| 85 mph (136.79 km/h) | 93.73 mph (150.84 km/h) |
| 90 mph (144.84 km/h) | 99.24 mph (159.71 km/h) |
| 95 mph (152.89 km/h) | 104.75 mph (168.58 km/h) |
| 100 mph (160.93 km/h) | 110.27 mph (177.45 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1686 | 1958 | 2109 | 2202 | 2302 | 2374 | 2453 | 2546 | 2675 | 2805 | 2948 | 3063 | 3271 | 3500 | 3680 | 3794 | 3859 | 4096 | 4426 | 5143 |
Better Fuel Economy Factory Ratios Increased Power
