-1.34%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 245/60R18, fitting 235/55R19 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 39.5 km/h | 25 mph | 25 mph |
| 60 km/h | 59.2 km/h | 37 mph | 37 mph |
| 80 km/h | 78.9 km/h | 50 mph | 49 mph |
| 100 km/h | 98.7 km/h | 62 mph | 61 mph |
| 120 km/h | 118.4 km/h | 75 mph | 74 mph |
Full comparison
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
235/55R19
Overall diameter741.1 mm · 29.18 in
Section width235 mm · 9.25 in
Sidewall height129.3 mm · 5.09 in
Circumference2328.2 mm · 91.7 in
Revolutions per mile691
Revolutions per km430
-1.34%Safe swap — speedometer error is minor
Original
Overall diameter751.2 mm · 29.57 in
Sidewall height147 mm
Circumference2,360 mm
Revolutions / mile681.9
New
Overall diameter741.1 mm · 29.18 in
Sidewall height129.3 mm
Circumference2,328.2 mm
Revolutions / mile691.2
Speedometer & odometer error
The new tire changes overall diameter by -1.34%. 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 | 39.5 km/h | 25 mph | 25 mph |
| 60 km/h | 59.2 km/h | 37 mph | 37 mph |
| 80 km/h | 78.9 km/h | 50 mph | 49 mph |
| 100 km/h | 98.7 km/h | 62 mph | 61 mph |
| 120 km/h | 118.4 km/h | 75 mph | 74 mph |
See individual specs: 245/60R18 · 235/55R19. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.