-1.32%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 235/60R16, fitting 225/55R17 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
235/60R16
Overall diameter688.4 mm · 27.10 in
Section width235 mm · 9.25 in
Sidewall height141.0 mm · 5.55 in
Circumference2162.7 mm · 85.1 in
Revolutions per mile744
Revolutions per km462
225/55R17
Overall diameter679.3 mm · 26.74 in
Section width225 mm · 8.86 in
Sidewall height123.8 mm · 4.87 in
Circumference2134.1 mm · 84.0 in
Revolutions per mile754
Revolutions per km469
-1.32%Safe swap — speedometer error is minor
Original
Overall diameter688.4 mm · 27.1 in
Sidewall height141 mm
Circumference2,162.7 mm
Revolutions / mile744.1
New
Overall diameter679.3 mm · 26.74 in
Sidewall height123.8 mm
Circumference2,134.1 mm
Revolutions / mile754.1
Speedometer & odometer error
The new tire changes overall diameter by -1.32%. 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: 235/60R16 · 225/55R17. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.