The new tire changes overall diameter by +2.51%. With a speedometer calibrated to the original tire, that same percentage is how far the speedometer and odometer read off — a taller tire means your true speed is higher than indicated and the odometer under-counts distance.
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 41 km/h | 25 mph | 25 mph |
| 60 km/h | 61.5 km/h | 37 mph | 38 mph |
| 80 km/h | 82 km/h | 50 mph | 51 mph |
| 100 km/h | 102.5 km/h | 62 mph | 64 mph |
| 120 km/h | 123 km/h | 75 mph | 76 mph |
Commonly compared with 245/45R17
- 245/45R17 vs 205/60R16 · 205/60R16 specs
- 245/45R17 vs 245/40R18 · 245/40R18 specs
- 245/45R17 vs 225/50R17 · 225/50R17 specs
- 245/45R17 vs 215/50R17 · 215/50R17 specs
- 245/45R17 vs 235/40R18 · 235/40R18 specs
- 245/45R17 vs 225/45R18 · 225/45R18 specs
- 245/45R17 vs 235/45R17 · 235/45R17 specs
- 245/45R17 vs 215/55R16 · 215/55R16 specs
FAQ
What is the overall diameter of a 245/45R17 tire?
A 245/45R17 tire has an overall diameter of about 25.68 inches (652 mm) and a section width of 245 mm.
What sizes can replace a 245/45R17 tire?
Sizes within about ±3% of 245/45R17's 25.7-inch diameter are the closest matches, such as 205/60R16, 245/40R18, 225/50R17. Use the calculator above to check the exact speedometer effect of any substitute.
Fitment & trouble codes
Changing tire size by more than about 3% shifts the speedometer, odometer and, on some vehicles, ABS/traction calibration — which can set wheel-speed-sensor or vehicle-speed codes. See C1234 (wheel speed sensor) and C0050 (rear wheel speed) if a warning light appears after a size change.