-9.25%Not recommended — recalibrate the speedometer
Speedometer error
With a speedometer calibrated to 285/45R22, fitting 295/35R21 makes it read as follows:
| Speedo shows | True speed | Speedo shows | True speed |
|---|---|---|---|
| 40 km/h | 36.3 km/h | 25 mph | 23 mph |
| 60 km/h | 54.5 km/h | 37 mph | 34 mph |
| 80 km/h | 72.6 km/h | 50 mph | 45 mph |
| 100 km/h | 90.8 km/h | 62 mph | 56 mph |
| 120 km/h | 108.9 km/h | 75 mph | 68 mph |
Full comparison
285/45R22
Overall diameter815.3 mm · 32.10 in
Section width285 mm · 11.22 in
Sidewall height128.3 mm · 5.05 in
Circumference2561.3 mm · 100.8 in
Revolutions per mile628
Revolutions per km390
295/35R21
Overall diameter739.9 mm · 29.13 in
Section width295 mm · 11.61 in
Sidewall height103.3 mm · 4.06 in
Circumference2324.5 mm · 91.5 in
Revolutions per mile692
Revolutions per km430
-9.25%Not recommended — recalibrate the speedometer
Original
Overall diameter815.3 mm · 32.1 in
Sidewall height128.3 mm
Circumference2,561.3 mm
Revolutions / mile628.3
New
Overall diameter739.9 mm · 29.13 in
Sidewall height103.3 mm
Circumference2,324.5 mm
Revolutions / mile692.4
Speedometer & odometer error
The new tire changes overall diameter by -9.25%. 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 | 36.3 km/h | 25 mph | 23 mph |
| 60 km/h | 54.5 km/h | 37 mph | 34 mph |
| 80 km/h | 72.6 km/h | 50 mph | 45 mph |
| 100 km/h | 90.8 km/h | 62 mph | 56 mph |
| 120 km/h | 108.9 km/h | 75 mph | 68 mph |
See individual specs: 285/45R22 · 295/35R21. A change this size can affect ABS/speed calibration — see wheel-speed codes if a light appears.