Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 235/30-18 | 235/40-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 23.55 (598.2) | 25.4 (645.2) | 1.85 (47) 7.9% |
| Width inches (mm) | 9.25 (235) | 9.25 (235) | 0 (0) 0% |
| Circum. inches (mm) | 73.99 (1879.3) | 79.8 (2026.96) | 5.81 (147.65) 7.9% |
| Sidewall Height inches (mm) | 2.78 (70.5) | 3.7 (94) | 0.93 (23.5) 33.3% |
| Revolutions per mile (km) | 856.35 (532.11) | 793.97 (493.35) | -62.38 (-38.76) -7.3% |
235/40-18 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.57 mph (34.72 km/h) |
| 25 mph (40.23 km/h) | 26.96 mph (43.39 km/h) |
| 30 mph (48.28 km/h) | 32.36 mph (52.07 km/h) |
| 35 mph (56.33 km/h) | 37.75 mph (60.75 km/h) |
| 40 mph (64.37 km/h) | 43.14 mph (69.43 km/h) |
| 45 mph (72.42 km/h) | 48.54 mph (78.11 km/h) |
| 50 mph (80.47 km/h) | 53.93 mph (86.79 km/h) |
| 55 mph (88.51 km/h) | 59.32 mph (95.47 km/h) |
| 60 mph (96.56 km/h) | 64.71 mph (104.15 km/h) |
| 65 mph (104.61 km/h) | 70.11 mph (112.83 km/h) |
| 70 mph (112.65 km/h) | 75.5 mph (121.51 km/h) |
| 75 mph (120.7 km/h) | 80.89 mph (130.18 km/h) |
| 80 mph (128.75 km/h) | 86.29 mph (138.86 km/h) |
| 85 mph (136.79 km/h) | 91.68 mph (147.54 km/h) |
| 90 mph (144.84 km/h) | 97.07 mph (156.22 km/h) |
| 95 mph (152.89 km/h) | 102.46 mph (164.9 km/h) |
| 100 mph (160.93 km/h) | 107.86 mph (173.58 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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