-2.01%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 205/65R15, fitting 195/65R15 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
205/65R15
Overall diameter647.5 mm · 25.49 in
Section width205 mm · 8.07 in
Sidewall height133.3 mm · 5.25 in
Circumference2034.2 mm · 80.1 in
Revolutions per mile791
Revolutions per km492
195/65R15
Overall diameter634.5 mm · 24.98 in
Section width195 mm · 7.68 in
Sidewall height126.8 mm · 4.99 in
Circumference1993.3 mm · 78.5 in
Revolutions per mile807
Revolutions per km502
-2.01%Safe swap — speedometer error is minor
Original
Overall diameter647.5 mm · 25.49 in
Sidewall height133.3 mm
Circumference2,034.2 mm
Revolutions / mile791.2
New
Overall diameter634.5 mm · 24.98 in
Sidewall height126.8 mm
Circumference1,993.3 mm
Revolutions / mile807.4
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: 205/65R15 · 195/65R15. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.