Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 235/60-18 | 255/45-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.1 (739.2) | 29.04 (737.5) | -0.07 (-1.7) -0.2% |
| Width inches (mm) | 9.25 (235) | 10.04 (255) | 0.79 (20) 8.5% |
| Circum. inches (mm) | 91.43 (2322.27) | 91.22 (2316.92) | -0.21 (-5.34) -0.2% |
| Sidewall Height inches (mm) | 5.55 (141) | 4.52 (114.75) | -1.03 (-26.25) -18.6% |
| Revolutions per mile (km) | 693.01 (430.61) | 694.6 (431.61) | 1.6 (0.99) 0.2% |
255/45-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.95 mph (32.11 km/h) |
| 25 mph (40.23 km/h) | 24.94 mph (40.14 km/h) |
| 30 mph (48.28 km/h) | 29.93 mph (48.17 km/h) |
| 35 mph (56.33 km/h) | 34.92 mph (56.2 km/h) |
| 40 mph (64.37 km/h) | 39.91 mph (64.23 km/h) |
| 45 mph (72.42 km/h) | 44.9 mph (72.25 km/h) |
| 50 mph (80.47 km/h) | 49.89 mph (80.28 km/h) |
| 55 mph (88.51 km/h) | 54.87 mph (88.31 km/h) |
| 60 mph (96.56 km/h) | 59.86 mph (96.34 km/h) |
| 65 mph (104.61 km/h) | 64.85 mph (104.37 km/h) |
| 70 mph (112.65 km/h) | 69.84 mph (112.4 km/h) |
| 75 mph (120.7 km/h) | 74.83 mph (120.42 km/h) |
| 80 mph (128.75 km/h) | 79.82 mph (128.45 km/h) |
| 85 mph (136.79 km/h) | 84.8 mph (136.48 km/h) |
| 90 mph (144.84 km/h) | 89.79 mph (144.51 km/h) |
| 95 mph (152.89 km/h) | 94.78 mph (152.54 km/h) |
| 100 mph (160.93 km/h) | 99.77 mph (160.56 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1768 | 2053 | 2211 | 2309 | 2415 | 2490 | 2572 | 2670 | 2806 | 2941 | 3091 | 3212 | 3430 | 3671 | 3859 | 3979 | 4047 | 4295 | 4641 | 5393 |
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