-3.10%Borderline — noticeable speedometer/odometer error
Speedometer error
With a speedometer calibrated to 265/60R18, fitting 245/60R18 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 38.8 km/h | 25 mph | 24 mph |
| 60 km/h | 58.1 km/h | 37 mph | 36 mph |
| 80 km/h | 77.5 km/h | 50 mph | 48 mph |
| 100 km/h | 96.9 km/h | 62 mph | 60 mph |
| 120 km/h | 116.3 km/h | 75 mph | 72 mph |
Full comparison
265/60R18
Overall diameter775.2 mm · 30.52 in
Section width265 mm · 10.43 in
Sidewall height159.0 mm · 6.26 in
Circumference2435.4 mm · 95.9 in
Revolutions per mile661
Revolutions per km411
245/60R18
Overall diameter751.2 mm · 29.57 in
Section width245 mm · 9.65 in
Sidewall height147.0 mm · 5.79 in
Circumference2360.0 mm · 92.9 in
Revolutions per mile682
Revolutions per km424
-3.1%Borderline — noticeable speedometer/odometer error
Original
Overall diameter775.2 mm · 30.52 in
Sidewall height159 mm
Circumference2,435.4 mm
Revolutions / mile660.8
New
Overall diameter751.2 mm · 29.57 in
Sidewall height147 mm
Circumference2,360 mm
Revolutions / mile681.9
Speedometer & odometer error
The new tire changes overall diameter by -3.1%. 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 | 38.8 km/h | 25 mph | 24 mph |
| 60 km/h | 58.1 km/h | 37 mph | 36 mph |
| 80 km/h | 77.5 km/h | 50 mph | 48 mph |
| 100 km/h | 96.9 km/h | 62 mph | 60 mph |
| 120 km/h | 116.3 km/h | 75 mph | 72 mph |
See individual specs: 265/60R18 · 245/60R18. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.