Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 120/70-21 | 100/70-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.61 (701.4) | 26.51 (673.4) | -1.1 (-28) -4% |
| Width inches (mm) | 4.72 (120) | 3.94 (100) | -0.79 (-20) -16.7% |
| Circum. inches (mm) | 86.75 (2203.51) | 83.29 (2115.55) | -3.46 (-87.96) -4% |
| Sidewall Height inches (mm) | 3.31 (84) | 2.76 (70) | -0.55 (-14) -16.7% |
| Revolutions per mile (km) | 730.35 (453.82) | 760.72 (472.69) | 30.37 (18.87) 4.2% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.2 mph (30.9 km/h) |
| 25 mph (40.23 km/h) | 24 mph (38.63 km/h) |
| 30 mph (48.28 km/h) | 28.8 mph (46.35 km/h) |
| 35 mph (56.33 km/h) | 33.6 mph (54.08 km/h) |
| 40 mph (64.37 km/h) | 38.4 mph (61.8 km/h) |
| 45 mph (72.42 km/h) | 43.2 mph (69.53 km/h) |
| 50 mph (80.47 km/h) | 48 mph (77.26 km/h) |
| 55 mph (88.51 km/h) | 52.8 mph (84.98 km/h) |
| 60 mph (96.56 km/h) | 57.6 mph (92.71 km/h) |
| 65 mph (104.61 km/h) | 62.41 mph (100.43 km/h) |
| 70 mph (112.65 km/h) | 67.21 mph (108.16 km/h) |
| 75 mph (120.7 km/h) | 72.01 mph (115.88 km/h) |
| 80 mph (128.75 km/h) | 76.81 mph (123.61 km/h) |
| 85 mph (136.79 km/h) | 81.61 mph (131.33 km/h) |
| 90 mph (144.84 km/h) | 86.41 mph (139.06 km/h) |
| 95 mph (152.89 km/h) | 91.21 mph (146.78 km/h) |
| 100 mph (160.93 km/h) | 96.01 mph (154.51 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1936 | 2249 | 2422 | 2529 | 2644 | 2727 | 2817 | 2924 | 3073 | 3221 | 3386 | 3518 | 3756 | 4020 | 4226 | 4358 | 4432 | 4704 | 5083 | 5907 |
Better Fuel Economy Factory Ratios Increased Power
