+4.91%Borderline — noticeable speedometer/odometer error
Speedometer error
With a speedometer calibrated to 245/45R19, fitting 255/50R19 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 42.0 km/h | 25 mph | 26 mph |
| 60 km/h | 62.9 km/h | 37 mph | 39 mph |
| 80 km/h | 83.9 km/h | 50 mph | 52 mph |
| 100 km/h | 104.9 km/h | 62 mph | 65 mph |
| 120 km/h | 125.9 km/h | 75 mph | 78 mph |
Full comparison
245/45R19
Overall diameter703.1 mm · 27.68 in
Section width245 mm · 9.65 in
Sidewall height110.3 mm · 4.34 in
Circumference2208.9 mm · 87.0 in
Revolutions per mile729
Revolutions per km453
255/50R19
Overall diameter737.6 mm · 29.04 in
Section width255 mm · 10.04 in
Sidewall height127.5 mm · 5.02 in
Circumference2317.2 mm · 91.2 in
Revolutions per mile695
Revolutions per km432
+4.91%Borderline — noticeable speedometer/odometer error
Original
Overall diameter703.1 mm · 27.68 in
Sidewall height110.3 mm
Circumference2,208.9 mm
Revolutions / mile728.6
New
Overall diameter737.6 mm · 29.04 in
Sidewall height127.5 mm
Circumference2,317.2 mm
Revolutions / mile694.5
Speedometer & odometer error
The new tire changes overall diameter by +4.91%. 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 | 42 km/h | 25 mph | 26 mph |
| 60 km/h | 62.9 km/h | 37 mph | 39 mph |
| 80 km/h | 83.9 km/h | 50 mph | 52 mph |
| 100 km/h | 104.9 km/h | 62 mph | 65 mph |
| 120 km/h | 125.9 km/h | 75 mph | 78 mph |
See individual specs: 245/45R19 · 255/50R19. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.