Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 175/90-18 | 255/40-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 30.4 (772.2) | 28.03 (712) | -2.37 (-60.2) -7.8% |
| Width inches (mm) | 6.89 (175) | 10.04 (255) | 3.15 (80) 45.7% |
| Circum. inches (mm) | 95.51 (2425.94) | 88.06 (2236.81) | -7.45 (-189.12) -7.8% |
| Sidewall Height inches (mm) | 6.2 (157.5) | 4.02 (102) | -2.19 (-55.5) -35.2% |
| Revolutions per mile (km) | 663.39 (412.21) | 719.48 (447.06) | 56.09 (34.85) 8.5% |
255/40-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 18.44 mph (29.68 km/h) |
| 25 mph (40.23 km/h) | 23.05 mph (37.1 km/h) |
| 30 mph (48.28 km/h) | 27.66 mph (44.52 km/h) |
| 35 mph (56.33 km/h) | 32.27 mph (51.94 km/h) |
| 40 mph (64.37 km/h) | 36.88 mph (59.36 km/h) |
| 45 mph (72.42 km/h) | 41.49 mph (66.77 km/h) |
| 50 mph (80.47 km/h) | 46.1 mph (74.19 km/h) |
| 55 mph (88.51 km/h) | 50.71 mph (81.61 km/h) |
| 60 mph (96.56 km/h) | 55.32 mph (89.03 km/h) |
| 65 mph (104.61 km/h) | 59.93 mph (96.45 km/h) |
| 70 mph (112.65 km/h) | 64.54 mph (103.87 km/h) |
| 75 mph (120.7 km/h) | 69.15 mph (111.29 km/h) |
| 80 mph (128.75 km/h) | 73.76 mph (118.71 km/h) |
| 85 mph (136.79 km/h) | 78.37 mph (126.13 km/h) |
| 90 mph (144.84 km/h) | 82.98 mph (133.55 km/h) |
| 95 mph (152.89 km/h) | 87.59 mph (140.97 km/h) |
| 100 mph (160.93 km/h) | 92.2 mph (148.39 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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