-0.33%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 265/70R16, fitting 245/70R17 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 39.9 km/h | 25 mph | 25 mph |
| 60 km/h | 59.8 km/h | 37 mph | 37 mph |
| 80 km/h | 79.7 km/h | 50 mph | 50 mph |
| 100 km/h | 99.7 km/h | 62 mph | 62 mph |
| 120 km/h | 119.6 km/h | 75 mph | 74 mph |
Full comparison
265/70R16
Overall diameter777.4 mm · 30.61 in
Section width265 mm · 10.43 in
Sidewall height185.5 mm · 7.30 in
Circumference2442.3 mm · 96.2 in
Revolutions per mile659
Revolutions per km409
245/70R17
Overall diameter774.8 mm · 30.50 in
Section width245 mm · 9.65 in
Sidewall height171.5 mm · 6.75 in
Circumference2434.1 mm · 95.8 in
Revolutions per mile661
Revolutions per km411
-0.33%Safe swap — speedometer error is minor
Original
Overall diameter777.4 mm · 30.61 in
Sidewall height185.5 mm
Circumference2,442.3 mm
Revolutions / mile659
New
Overall diameter774.8 mm · 30.5 in
Sidewall height171.5 mm
Circumference2,434.1 mm
Revolutions / mile661.2
Speedometer & odometer error
The new tire changes overall diameter by -0.33%. 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 | 39.9 km/h | 25 mph | 25 mph |
| 60 km/h | 59.8 km/h | 37 mph | 37 mph |
| 80 km/h | 79.7 km/h | 50 mph | 50 mph |
| 100 km/h | 99.7 km/h | 62 mph | 62 mph |
| 120 km/h | 119.6 km/h | 75 mph | 74 mph |
See individual specs: 265/70R16 · 245/70R17. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.