-0.93%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 235/60R16, fitting 215/70R15 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 39.6 km/h | 25 mph | 25 mph |
| 60 km/h | 59.4 km/h | 37 mph | 37 mph |
| 80 km/h | 79.3 km/h | 50 mph | 49 mph |
| 100 km/h | 99.1 km/h | 62 mph | 62 mph |
| 120 km/h | 118.9 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
215/70R15
Overall diameter682.0 mm · 26.85 in
Section width215 mm · 8.46 in
Sidewall height150.5 mm · 5.93 in
Circumference2142.6 mm · 84.4 in
Revolutions per mile751
Revolutions per km467
-0.93%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 diameter682 mm · 26.85 in
Sidewall height150.5 mm
Circumference2,142.6 mm
Revolutions / mile751.1
Speedometer & odometer error
The new tire changes overall diameter by -0.93%. 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 | 39.6 km/h | 25 mph | 25 mph |
| 60 km/h | 59.4 km/h | 37 mph | 37 mph |
| 80 km/h | 79.3 km/h | 50 mph | 49 mph |
| 100 km/h | 99.1 km/h | 62 mph | 62 mph |
| 120 km/h | 118.9 km/h | 75 mph | 74 mph |
See individual specs: 235/60R16 · 215/70R15. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.