+1.34%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 255/55R18, fitting 265/50R19 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 40.5 km/h | 25 mph | 25 mph |
| 60 km/h | 60.8 km/h | 37 mph | 38 mph |
| 80 km/h | 81.1 km/h | 50 mph | 50 mph |
| 100 km/h | 101.3 km/h | 62 mph | 63 mph |
| 120 km/h | 121.6 km/h | 75 mph | 76 mph |
Full comparison
255/55R18
Overall diameter737.7 mm · 29.04 in
Section width255 mm · 10.04 in
Sidewall height140.3 mm · 5.52 in
Circumference2317.6 mm · 91.2 in
Revolutions per mile694
Revolutions per km431
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
+1.34%Safe swap — speedometer error is minor
Original
Overall diameter737.7 mm · 29.04 in
Sidewall height140.3 mm
Circumference2,317.6 mm
Revolutions / mile694.4
New
Overall diameter747.6 mm · 29.43 in
Sidewall height132.5 mm
Circumference2,348.7 mm
Revolutions / mile685.2
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 | 40.5 km/h | 25 mph | 25 mph |
| 60 km/h | 60.8 km/h | 37 mph | 38 mph |
| 80 km/h | 81.1 km/h | 50 mph | 50 mph |
| 100 km/h | 101.3 km/h | 62 mph | 63 mph |
| 120 km/h | 121.6 km/h | 75 mph | 76 mph |
See individual specs: 255/55R18 · 265/50R19. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.