-1.12%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 265/50R19, fitting 235/60R18 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 39.6 km/h | 25 mph | 25 mph |
| 60 km/h | 59.3 km/h | 37 mph | 37 mph |
| 80 km/h | 79.1 km/h | 50 mph | 49 mph |
| 100 km/h | 98.9 km/h | 62 mph | 61 mph |
| 120 km/h | 118.7 km/h | 75 mph | 74 mph |
Full comparison
265/50R19
Overall diameter747.6 mm · 29.43 in
Section width265 mm · 10.43 in
Sidewall height132.5 mm · 5.22 in
Circumference2348.7 mm · 92.5 in
Revolutions per mile685
Revolutions per km426
235/60R18
Overall diameter739.2 mm · 29.10 in
Section width235 mm · 9.25 in
Sidewall height141.0 mm · 5.55 in
Circumference2322.3 mm · 91.4 in
Revolutions per mile693
Revolutions per km431
-1.12%Safe swap — speedometer error is minor
Original
Overall diameter747.6 mm · 29.43 in
Sidewall height132.5 mm
Circumference2,348.7 mm
Revolutions / mile685.2
New
Overall diameter739.2 mm · 29.1 in
Sidewall height141 mm
Circumference2,322.3 mm
Revolutions / mile693
Speedometer & odometer error
The new tire changes overall diameter by -1.12%. 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 | 39.6 km/h | 25 mph | 25 mph |
| 60 km/h | 59.3 km/h | 37 mph | 37 mph |
| 80 km/h | 79.1 km/h | 50 mph | 49 mph |
| 100 km/h | 98.9 km/h | 62 mph | 61 mph |
| 120 km/h | 118.7 km/h | 75 mph | 74 mph |
See individual specs: 265/50R19 · 235/60R18. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.