Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 255/30-21 | 255/85-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 27.02 (686.4) | 35.07 (890.7) | 8.04 (204.3) 29.8% |
| Width inches (mm) | 10.04 (255) | 10.04 (255) | 0 (0) 0% |
| Circum. inches (mm) | 84.9 (2156.39) | 110.17 (2798.22) | 25.27 (641.83) 29.8% |
| Sidewall Height inches (mm) | 3.01 (76.5) | 8.53 (216.75) | 5.52 (140.25) 183.3% |
| Revolutions per mile (km) | 746.31 (463.74) | 575.13 (357.37) | -171.18 (-106.37) -22.9% |
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 25.95 mph (41.77 km/h) |
| 25 mph (40.23 km/h) | 32.44 mph (52.21 km/h) |
| 30 mph (48.28 km/h) | 38.93 mph (62.65 km/h) |
| 35 mph (56.33 km/h) | 45.42 mph (73.09 km/h) |
| 40 mph (64.37 km/h) | 51.91 mph (83.53 km/h) |
| 45 mph (72.42 km/h) | 58.39 mph (93.98 km/h) |
| 50 mph (80.47 km/h) | 64.88 mph (104.42 km/h) |
| 55 mph (88.51 km/h) | 71.37 mph (114.86 km/h) |
| 60 mph (96.56 km/h) | 77.86 mph (125.3 km/h) |
| 65 mph (104.61 km/h) | 84.35 mph (135.74 km/h) |
| 70 mph (112.65 km/h) | 90.83 mph (146.18 km/h) |
| 75 mph (120.7 km/h) | 97.32 mph (156.63 km/h) |
| 80 mph (128.75 km/h) | 103.81 mph (167.07 km/h) |
| 85 mph (136.79 km/h) | 110.3 mph (177.51 km/h) |
| 90 mph (144.84 km/h) | 116.79 mph (187.95 km/h) |
| 95 mph (152.89 km/h) | 123.28 mph (198.39 km/h) |
| 100 mph (160.93 km/h) | 129.76 mph (208.84 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1464 | 1700 | 1831 | 1912 | 1999 | 2061 | 2130 | 2211 | 2323 | 2435 | 2560 | 2659 | 2840 | 3039 | 3195 | 3295 | 3351 | 3556 | 3843 | 4466 |
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