Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 145/80-18 | 255/40-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.13 (689.2) | 28.03 (712) | 0.9 (22.8) 3.3% |
| Width inches (mm) | 5.71 (145) | 10.04 (255) | 4.33 (110) 75.9% |
| Circum. inches (mm) | 85.24 (2165.19) | 88.06 (2236.81) | 2.82 (71.63) 3.3% |
| Sidewall Height inches (mm) | 4.57 (116) | 4.02 (102) | -0.55 (-14) -12.1% |
| Revolutions per mile (km) | 743.28 (461.85) | 719.48 (447.06) | -23.8 (-14.79) -3.2% |
255/40-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.66 mph (33.25 km/h) |
| 25 mph (40.23 km/h) | 25.83 mph (41.56 km/h) |
| 30 mph (48.28 km/h) | 30.99 mph (49.88 km/h) |
| 35 mph (56.33 km/h) | 36.16 mph (58.19 km/h) |
| 40 mph (64.37 km/h) | 41.32 mph (66.5 km/h) |
| 45 mph (72.42 km/h) | 46.49 mph (74.82 km/h) |
| 50 mph (80.47 km/h) | 51.65 mph (83.13 km/h) |
| 55 mph (88.51 km/h) | 56.82 mph (91.44 km/h) |
| 60 mph (96.56 km/h) | 61.98 mph (99.76 km/h) |
| 65 mph (104.61 km/h) | 67.15 mph (108.07 km/h) |
| 70 mph (112.65 km/h) | 72.32 mph (116.38 km/h) |
| 75 mph (120.7 km/h) | 77.48 mph (124.69 km/h) |
| 80 mph (128.75 km/h) | 82.65 mph (133.01 km/h) |
| 85 mph (136.79 km/h) | 87.81 mph (141.32 km/h) |
| 90 mph (144.84 km/h) | 92.98 mph (149.63 km/h) |
| 95 mph (152.89 km/h) | 98.14 mph (157.95 km/h) |
| 100 mph (160.93 km/h) | 103.31 mph (166.26 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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