The new tire changes overall diameter by -17.92%. 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 | 32.8 km/h | 25 mph | 20 mph |
| 60 km/h | 49.2 km/h | 37 mph | 31 mph |
| 80 km/h | 65.7 km/h | 50 mph | 41 mph |
| 100 km/h | 82.1 km/h | 62 mph | 51 mph |
| 120 km/h | 98.5 km/h | 75 mph | 61 mph |
Commonly compared with 275/65R18
- 275/65R18 vs 255/70R18 · 255/70R18 specs
- 275/65R18 vs 275/70R17 · 275/70R17 specs
- 275/65R18 vs 265/70R17 · 265/70R17 specs
- 275/65R18 vs 265/65R18 · 265/65R18 specs
- 275/65R18 vs 285/60R18 · 285/60R18 specs
- 275/65R18 vs 285/70R17 · 285/70R17 specs
- 275/65R18 vs 275/70R18 · 275/70R18 specs
- 275/65R18 vs 265/65R17 · 265/65R17 specs
FAQ
What is the overall diameter of a 275/65R18 tire?
A 275/65R18 tire has an overall diameter of about 32.07 inches (815 mm) and a section width of 275 mm.
What sizes can replace a 275/65R18 tire?
Sizes within about ±3% of 275/65R18's 32.1-inch diameter are the closest matches, such as 255/70R18, 275/70R17, 265/70R17. 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.