+0.37%Safe swap — speedometer error is minor
Speedometer error
With a speedometer calibrated to 285/70R17, fitting 285/75R16 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 40.1 km/h | 25 mph | 25 mph |
| 60 km/h | 60.2 km/h | 37 mph | 37 mph |
| 80 km/h | 80.3 km/h | 50 mph | 50 mph |
| 100 km/h | 100.4 km/h | 62 mph | 62 mph |
| 120 km/h | 120.4 km/h | 75 mph | 75 mph |
Full comparison
285/70R17
Overall diameter830.8 mm · 32.71 in
Section width285 mm · 11.22 in
Sidewall height199.5 mm · 7.85 in
Circumference2610.0 mm · 102.8 in
Revolutions per mile617
Revolutions per km383
285/75R16
Overall diameter833.9 mm · 32.83 in
Section width285 mm · 11.22 in
Sidewall height213.8 mm · 8.42 in
Circumference2619.8 mm · 103.1 in
Revolutions per mile614
Revolutions per km382
+0.37%Safe swap — speedometer error is minor
Original
Overall diameter830.8 mm · 32.71 in
Sidewall height199.5 mm
Circumference2,610 mm
Revolutions / mile616.6
New
Overall diameter833.9 mm · 32.83 in
Sidewall height213.8 mm
Circumference2,619.8 mm
Revolutions / mile614.3
Speedometer & odometer error
The new tire changes overall diameter by +0.37%. 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 | 40.1 km/h | 25 mph | 25 mph |
| 60 km/h | 60.2 km/h | 37 mph | 37 mph |
| 80 km/h | 80.3 km/h | 50 mph | 50 mph |
| 100 km/h | 100.4 km/h | 62 mph | 62 mph |
| 120 km/h | 120.4 km/h | 75 mph | 75 mph |
See individual specs: 285/70R17 · 285/75R16. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.