Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 145/85-18 | 255/40-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.7 (703.7) | 28.03 (712) | 0.33 (8.3) 1.2% |
| Width inches (mm) | 5.71 (145) | 10.04 (255) | 4.33 (110) 75.9% |
| Circum. inches (mm) | 87.04 (2210.74) | 88.06 (2236.81) | 1.03 (26.08) 1.2% |
| Sidewall Height inches (mm) | 4.85 (123.25) | 4.02 (102) | -0.84 (-21.25) -17.2% |
| Revolutions per mile (km) | 727.97 (452.34) | 719.48 (447.06) | -8.49 (-5.27) -1.2% |
255/40-20 Tires
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) | 25.29 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 (73.27 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 (113.98 km/h) |
| 75 mph (120.7 km/h) | 75.88 mph (122.12 km/h) |
| 80 mph (128.75 km/h) | 80.94 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 (162.83 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 |
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