-0.85%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 205/50R17, fitting 225/50R16 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 39.7 km/h | 25 mph | 25 mph |
| 60 km/h | 59.5 km/h | 37 mph | 37 mph |
| 80 km/h | 79.3 km/h | 50 mph | 49 mph |
| 100 km/h | 99.2 km/h | 62 mph | 62 mph |
| 120 km/h | 119.0 km/h | 75 mph | 74 mph |
Full comparison
205/50R17
Overall diameter636.8 mm · 25.07 in
Section width205 mm · 8.07 in
Sidewall height102.5 mm · 4.04 in
Circumference2000.6 mm · 78.8 in
Revolutions per mile804
Revolutions per km500
225/50R16
Overall diameter631.4 mm · 24.86 in
Section width225 mm · 8.86 in
Sidewall height112.5 mm · 4.43 in
Circumference1983.6 mm · 78.1 in
Revolutions per mile811
Revolutions per km504
-0.85%Safe swap — speedometer error is minor
Original
Overall diameter636.8 mm · 25.07 in
Sidewall height102.5 mm
Circumference2,000.6 mm
Revolutions / mile804.4
New
Overall diameter631.4 mm · 24.86 in
Sidewall height112.5 mm
Circumference1,983.6 mm
Revolutions / mile811.3
Speedometer & odometer error
The new tire changes overall diameter by -0.85%. 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 | 39.7 km/h | 25 mph | 25 mph |
| 60 km/h | 59.5 km/h | 37 mph | 37 mph |
| 80 km/h | 79.3 km/h | 50 mph | 49 mph |
| 100 km/h | 99.2 km/h | 62 mph | 62 mph |
| 120 km/h | 119 km/h | 75 mph | 74 mph |
See individual specs: 205/50R17 · 225/50R16. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.