The new tire changes overall diameter by -13.69%. 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 | 34.5 km/h | 25 mph | 21 mph |
| 60 km/h | 51.8 km/h | 37 mph | 32 mph |
| 80 km/h | 69 km/h | 50 mph | 43 mph |
| 100 km/h | 86.3 km/h | 62 mph | 54 mph |
| 120 km/h | 103.6 km/h | 75 mph | 64 mph |
Commonly compared with 245/70R17
- 245/70R17 vs 265/60R18 · 265/60R18 specs
- 245/70R17 vs 245/75R16 · 245/75R16 specs
- 245/70R17 vs 265/65R17 · 265/65R17 specs
- 245/70R17 vs 265/70R16 · 265/70R16 specs
- 245/70R17 vs 255/65R17 · 255/65R17 specs
- 245/70R17 vs 255/60R18 · 255/60R18 specs
- 245/70R17 vs 245/60R18 · 245/60R18 specs
- 245/70R17 vs 285/60R18 · 285/60R18 specs
FAQ
What is the overall diameter of a 245/70R17 tire?
A 245/70R17 tire has an overall diameter of about 30.50 inches (775 mm) and a section width of 245 mm.
What sizes can replace a 245/70R17 tire?
Sizes within about ±3% of 245/70R17's 30.5-inch diameter are the closest matches, such as 265/60R18, 245/75R16, 265/65R17. 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.