Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/30-18 | 235/40-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 24.73 (628.2) | 25.4 (645.2) | 0.67 (17) 2.7% |
| Width inches (mm) | 11.22 (285) | 9.25 (235) | -1.97 (-50) -17.5% |
| Circum. inches (mm) | 77.7 (1973.55) | 79.8 (2026.96) | 2.1 (53.41) 2.7% |
| Sidewall Height inches (mm) | 3.37 (85.5) | 3.7 (94) | 0.33 (8.5) 9.9% |
| Revolutions per mile (km) | 815.46 (506.7) | 793.97 (493.35) | -21.49 (-13.35) -2.6% |
235/40-18 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 20.54 mph (33.06 km/h) |
| 25 mph (40.23 km/h) | 25.68 mph (41.32 km/h) |
| 30 mph (48.28 km/h) | 30.81 mph (49.59 km/h) |
| 35 mph (56.33 km/h) | 35.95 mph (57.85 km/h) |
| 40 mph (64.37 km/h) | 41.08 mph (66.12 km/h) |
| 45 mph (72.42 km/h) | 46.22 mph (74.38 km/h) |
| 50 mph (80.47 km/h) | 51.35 mph (82.64 km/h) |
| 55 mph (88.51 km/h) | 56.49 mph (90.91 km/h) |
| 60 mph (96.56 km/h) | 61.62 mph (99.17 km/h) |
| 65 mph (104.61 km/h) | 66.76 mph (107.44 km/h) |
| 70 mph (112.65 km/h) | 71.89 mph (115.7 km/h) |
| 75 mph (120.7 km/h) | 77.03 mph (123.97 km/h) |
| 80 mph (128.75 km/h) | 82.16 mph (132.23 km/h) |
| 85 mph (136.79 km/h) | 87.3 mph (140.5 km/h) |
| 90 mph (144.84 km/h) | 92.44 mph (148.76 km/h) |
| 95 mph (152.89 km/h) | 97.57 mph (157.03 km/h) |
| 100 mph (160.93 km/h) | 102.71 mph (165.29 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2021 | 2347 | 2528 | 2640 | 2760 | 2846 | 2940 | 3052 | 3207 | 3362 | 3534 | 3671 | 3921 | 4196 | 4411 | 4548 | 4626 | 4909 | 5305 | 6165 |
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