-3.52%Borderline — noticeable speedometer/odometer error
Speedometer error
With a speedometer calibrated to 225/70R16, fitting 225/70R15 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 38.6 km/h | 25 mph | 24 mph |
| 60 km/h | 57.9 km/h | 37 mph | 36 mph |
| 80 km/h | 77.2 km/h | 50 mph | 48 mph |
| 100 km/h | 96.5 km/h | 62 mph | 60 mph |
| 120 km/h | 115.8 km/h | 75 mph | 72 mph |
Full comparison
225/70R16
Overall diameter721.4 mm · 28.40 in
Section width225 mm · 8.86 in
Sidewall height157.5 mm · 6.20 in
Circumference2266.3 mm · 89.2 in
Revolutions per mile710
Revolutions per km441
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
-3.52%Borderline — noticeable speedometer/odometer error
Original
Overall diameter721.4 mm · 28.4 in
Sidewall height157.5 mm
Circumference2,266.3 mm
Revolutions / mile710.1
New
Overall diameter696 mm · 27.4 in
Sidewall height157.5 mm
Circumference2,186.5 mm
Revolutions / mile736
Speedometer & odometer error
The new tire changes overall diameter by -3.52%. 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 | 38.6 km/h | 25 mph | 24 mph |
| 60 km/h | 57.9 km/h | 37 mph | 36 mph |
| 80 km/h | 77.2 km/h | 50 mph | 48 mph |
| 100 km/h | 96.5 km/h | 62 mph | 60 mph |
| 120 km/h | 115.8 km/h | 75 mph | 72 mph |
See individual specs: 225/70R16 · 225/70R15. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.