Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 285/30-18 | 285/40-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 24.73 (628.2) | 26.98 (685.2) | 2.24 (57) 9.1% |
| Width inches (mm) | 11.22 (285) | 11.22 (285) | 0 (0) 0% |
| Circum. inches (mm) | 77.7 (1973.55) | 84.75 (2152.62) | 7.05 (179.07) 9.1% |
| Sidewall Height inches (mm) | 3.37 (85.5) | 4.49 (114) | 1.12 (28.5) 33.3% |
| Revolutions per mile (km) | 815.46 (506.7) | 747.62 (464.55) | -67.84 (-42.15) -8.3% |
285/40-18 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 21.81 mph (35.11 km/h) |
| 25 mph (40.23 km/h) | 27.27 mph (43.88 km/h) |
| 30 mph (48.28 km/h) | 32.72 mph (52.66 km/h) |
| 35 mph (56.33 km/h) | 38.18 mph (61.44 km/h) |
| 40 mph (64.37 km/h) | 43.63 mph (70.21 km/h) |
| 45 mph (72.42 km/h) | 49.08 mph (78.99 km/h) |
| 50 mph (80.47 km/h) | 54.54 mph (87.77 km/h) |
| 55 mph (88.51 km/h) | 59.99 mph (96.55 km/h) |
| 60 mph (96.56 km/h) | 65.44 mph (105.32 km/h) |
| 65 mph (104.61 km/h) | 70.9 mph (114.1 km/h) |
| 70 mph (112.65 km/h) | 76.35 mph (122.88 km/h) |
| 75 mph (120.7 km/h) | 81.81 mph (131.65 km/h) |
| 80 mph (128.75 km/h) | 87.26 mph (140.43 km/h) |
| 85 mph (136.79 km/h) | 92.71 mph (149.21 km/h) |
| 90 mph (144.84 km/h) | 98.17 mph (157.98 km/h) |
| 95 mph (152.89 km/h) | 103.62 mph (166.76 km/h) |
| 100 mph (160.93 km/h) | 109.07 mph (175.54 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1903 | 2210 | 2380 | 2485 | 2599 | 2680 | 2769 | 2874 | 3020 | 3166 | 3327 | 3457 | 3692 | 3951 | 4153 | 4283 | 4356 | 4623 | 4995 | 5805 |
Better Fuel Economy Factory Ratios Increased Power
