Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 245/40-21 | 255/45-20 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 28.72 (729.4) | 29.04 (737.5) | 0.32 (8.1) 1.1% |
| Width inches (mm) | 9.65 (245) | 10.04 (255) | 0.39 (10) 4.1% |
| Circum. inches (mm) | 90.22 (2291.48) | 91.22 (2316.92) | 1 (25.45) 1.1% |
| Sidewall Height inches (mm) | 3.86 (98) | 4.52 (114.75) | 0.66 (16.75) 17.1% |
| Revolutions per mile (km) | 702.32 (436.4) | 694.6 (431.61) | -7.71 (-4.79) -1.1% |
255/45-20 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.22 mph (32.54 km/h) |
| 25 mph (40.23 km/h) | 25.28 mph (40.68 km/h) |
| 30 mph (48.28 km/h) | 30.33 mph (48.82 km/h) |
| 35 mph (56.33 km/h) | 35.39 mph (56.95 km/h) |
| 40 mph (64.37 km/h) | 40.44 mph (65.09 km/h) |
| 45 mph (72.42 km/h) | 45.5 mph (73.22 km/h) |
| 50 mph (80.47 km/h) | 50.56 mph (81.36 km/h) |
| 55 mph (88.51 km/h) | 55.61 mph (89.5 km/h) |
| 60 mph (96.56 km/h) | 60.67 mph (97.63 km/h) |
| 65 mph (104.61 km/h) | 65.72 mph (105.77 km/h) |
| 70 mph (112.65 km/h) | 70.78 mph (113.91 km/h) |
| 75 mph (120.7 km/h) | 75.83 mph (122.04 km/h) |
| 80 mph (128.75 km/h) | 80.89 mph (130.18 km/h) |
| 85 mph (136.79 km/h) | 85.94 mph (138.31 km/h) |
| 90 mph (144.84 km/h) | 91 mph (146.45 km/h) |
| 95 mph (152.89 km/h) | 96.05 mph (154.59 km/h) |
| 100 mph (160.93 km/h) | 101.11 mph (162.72 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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