-0.06%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 235/45R17, fitting 215/55R16 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 40.0 km/h | 25 mph | 25 mph |
| 60 km/h | 60.0 km/h | 37 mph | 37 mph |
| 80 km/h | 80.0 km/h | 50 mph | 50 mph |
| 100 km/h | 99.9 km/h | 62 mph | 62 mph |
| 120 km/h | 119.9 km/h | 75 mph | 75 mph |
Full comparison
235/45R17
Overall diameter643.3 mm · 25.33 in
Section width235 mm · 9.25 in
Sidewall height105.8 mm · 4.16 in
Circumference2021.0 mm · 79.6 in
Revolutions per mile796
Revolutions per km495
215/55R16
Overall diameter642.9 mm · 25.31 in
Section width215 mm · 8.46 in
Sidewall height118.3 mm · 4.66 in
Circumference2019.7 mm · 79.5 in
Revolutions per mile797
Revolutions per km495
-0.06%Safe swap — speedometer error is minor
Original
Overall diameter643.3 mm · 25.33 in
Sidewall height105.8 mm
Circumference2,021 mm
Revolutions / mile796.3
New
Overall diameter642.9 mm · 25.31 in
Sidewall height118.3 mm
Circumference2,019.7 mm
Revolutions / mile796.8
Speedometer & odometer error
The new tire changes overall diameter by -0.06%. 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 km/h | 25 mph | 25 mph |
| 60 km/h | 60 km/h | 37 mph | 37 mph |
| 80 km/h | 80 km/h | 50 mph | 50 mph |
| 100 km/h | 99.9 km/h | 62 mph | 62 mph |
| 120 km/h | 119.9 km/h | 75 mph | 75 mph |
See individual specs: 235/45R17 · 215/55R16. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.