Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 165/90-18 | 255/40-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.69 (754.2) | 28.03 (712) | -1.66 (-42.2) -5.6% |
| Width inches (mm) | 6.5 (165) | 10.04 (255) | 3.54 (90) 54.5% |
| Circum. inches (mm) | 93.28 (2369.39) | 88.06 (2236.81) | -5.22 (-132.58) -5.6% |
| Sidewall Height inches (mm) | 5.85 (148.5) | 4.02 (102) | -1.83 (-46.5) -31.3% |
| Revolutions per mile (km) | 679.22 (422.05) | 719.48 (447.06) | 40.26 (25.01) 5.9% |
255/40-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 18.88 mph (30.39 km/h) |
| 25 mph (40.23 km/h) | 23.6 mph (37.98 km/h) |
| 30 mph (48.28 km/h) | 28.32 mph (45.58 km/h) |
| 35 mph (56.33 km/h) | 33.04 mph (53.18 km/h) |
| 40 mph (64.37 km/h) | 37.76 mph (60.77 km/h) |
| 45 mph (72.42 km/h) | 42.48 mph (68.37 km/h) |
| 50 mph (80.47 km/h) | 47.2 mph (75.96 km/h) |
| 55 mph (88.51 km/h) | 51.92 mph (83.56 km/h) |
| 60 mph (96.56 km/h) | 56.64 mph (91.16 km/h) |
| 65 mph (104.61 km/h) | 61.36 mph (98.75 km/h) |
| 70 mph (112.65 km/h) | 66.08 mph (106.35 km/h) |
| 75 mph (120.7 km/h) | 70.8 mph (113.95 km/h) |
| 80 mph (128.75 km/h) | 75.52 mph (121.54 km/h) |
| 85 mph (136.79 km/h) | 80.24 mph (129.14 km/h) |
| 90 mph (144.84 km/h) | 84.96 mph (136.74 km/h) |
| 95 mph (152.89 km/h) | 89.68 mph (144.33 km/h) |
| 100 mph (160.93 km/h) | 94.4 mph (151.93 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1831 | 2127 | 2291 | 2392 | 2501 | 2579 | 2665 | 2766 | 2906 | 3046 | 3202 | 3327 | 3553 | 3802 | 3997 | 4122 | 4192 | 4449 | 4807 | 5586 |
Better Fuel Economy Factory Ratios Increased Power
