Tire Size Finder (optional):
Stock Sizes
- 255/75-16
Plus Sizes
- 255/75-16
Accepts P-Metric and Inches
| 235/45-21 | 255/55-18 | Difference | |
|---|---|---|---|
| Diameter inches (mm) | 29.33 (744.9) | 29.04 (737.7) | -0.28 (-7.2) -1% |
| Width inches (mm) | 9.25 (235) | 10.04 (255) | 0.79 (20) 8.5% |
| Circum. inches (mm) | 92.13 (2340.17) | 91.24 (2317.55) | -0.89 (-22.62) -1% |
| Sidewall Height inches (mm) | 4.16 (105.75) | 5.52 (140.25) | 1.36 (34.5) 32.6% |
| Revolutions per mile (km) | 687.7 (427.32) | 694.42 (431.49) | 6.71 (4.17) 1% |
255/55-18 Tires
Speedometer Difference
| Speedo Reading | Actual Speed |
|---|---|
| 20 mph (32.19 km/h) | 19.81 mph (31.88 km/h) |
| 25 mph (40.23 km/h) | 24.76 mph (39.84 km/h) |
| 30 mph (48.28 km/h) | 29.71 mph (47.81 km/h) |
| 35 mph (56.33 km/h) | 34.66 mph (55.78 km/h) |
| 40 mph (64.37 km/h) | 39.61 mph (63.75 km/h) |
| 45 mph (72.42 km/h) | 44.57 mph (71.72 km/h) |
| 50 mph (80.47 km/h) | 49.52 mph (79.69 km/h) |
| 55 mph (88.51 km/h) | 54.47 mph (87.66 km/h) |
| 60 mph (96.56 km/h) | 59.42 mph (95.63 km/h) |
| 65 mph (104.61 km/h) | 64.37 mph (103.6 km/h) |
| 70 mph (112.65 km/h) | 69.32 mph (111.57 km/h) |
| 75 mph (120.7 km/h) | 74.28 mph (119.53 km/h) |
| 80 mph (128.75 km/h) | 79.23 mph (127.5 km/h) |
| 85 mph (136.79 km/h) | 84.18 mph (135.47 km/h) |
| 90 mph (144.84 km/h) | 89.13 mph (143.44 km/h) |
| 95 mph (152.89 km/h) | 94.08 mph (151.41 km/h) |
| 100 mph (160.93 km/h) | 99.03 mph (159.38 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1767 | 2053 | 2211 | 2309 | 2414 | 2489 | 2572 | 2670 | 2805 | 2940 | 3091 | 3211 | 3429 | 3670 | 3858 | 3978 | 4046 | 4294 | 4640 | 5392 |
Better Fuel Economy Factory Ratios Increased Power
