Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 155/90-18 | 235/45-21 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.98 (736.2) | 29.33 (744.9) | 0.34 (8.7) 1.2% |
| Width inches (mm) | 6.1 (155) | 9.25 (235) | 3.15 (80) 51.6% |
| Circum. inches (mm) | 91.06 (2312.84) | 92.13 (2340.17) | 1.08 (27.33) 1.2% |
| Sidewall Height inches (mm) | 5.49 (139.5) | 4.16 (105.75) | -1.33 (-33.75) -24.2% |
| Revolutions per mile (km) | 695.83 (432.37) | 687.7 (427.32) | -8.13 (-5.05) -1.2% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.24 mph (32.57 km/h) |
| 25 mph (40.23 km/h) | 25.3 mph (40.71 km/h) |
| 30 mph (48.28 km/h) | 30.35 mph (48.85 km/h) |
| 35 mph (56.33 km/h) | 35.41 mph (56.99 km/h) |
| 40 mph (64.37 km/h) | 40.47 mph (65.13 km/h) |
| 45 mph (72.42 km/h) | 45.53 mph (73.28 km/h) |
| 50 mph (80.47 km/h) | 50.59 mph (81.42 km/h) |
| 55 mph (88.51 km/h) | 55.65 mph (89.56 km/h) |
| 60 mph (96.56 km/h) | 60.71 mph (97.7 km/h) |
| 65 mph (104.61 km/h) | 65.77 mph (105.84 km/h) |
| 70 mph (112.65 km/h) | 70.83 mph (113.99 km/h) |
| 75 mph (120.7 km/h) | 75.89 mph (122.13 km/h) |
| 80 mph (128.75 km/h) | 80.95 mph (130.27 km/h) |
| 85 mph (136.79 km/h) | 86 mph (138.41 km/h) |
| 90 mph (144.84 km/h) | 91.06 mph (146.55 km/h) |
| 95 mph (152.89 km/h) | 96.12 mph (154.69 km/h) |
| 100 mph (160.93 km/h) | 101.18 mph (162.84 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1750 | 2033 | 2189 | 2286 | 2391 | 2465 | 2547 | 2644 | 2778 | 2912 | 3061 | 3180 | 3396 | 3634 | 3820 | 3940 | 4007 | 4252 | 4595 | 5340 |
Better Fuel Economy Factory Ratios Increased Power
