-2.01%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 225/70R15, fitting 215/70R15 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 39.2 km/h | 25 mph | 24 mph |
| 60 km/h | 58.8 km/h | 37 mph | 37 mph |
| 80 km/h | 78.4 km/h | 50 mph | 49 mph |
| 100 km/h | 98.0 km/h | 62 mph | 61 mph |
| 120 km/h | 117.6 km/h | 75 mph | 73 mph |
Full comparison
225/70R15
Overall diameter696.0 mm · 27.40 in
Section width225 mm · 8.86 in
Sidewall height157.5 mm · 6.20 in
Circumference2186.5 mm · 86.1 in
Revolutions per mile736
Revolutions per km457
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
-2.01%Safe swap — speedometer error is minor
Original
Overall diameter696 mm · 27.4 in
Sidewall height157.5 mm
Circumference2,186.5 mm
Revolutions / mile736
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 -2.01%. 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 | 39.2 km/h | 25 mph | 24 mph |
| 60 km/h | 58.8 km/h | 37 mph | 37 mph |
| 80 km/h | 78.4 km/h | 50 mph | 49 mph |
| 100 km/h | 98 km/h | 62 mph | 61 mph |
| 120 km/h | 117.6 km/h | 75 mph | 73 mph |
See individual specs: 225/70R15 · 215/70R15. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.