215/40R17 vs 225/45R17
225/45R17 is outside the ±3% rule as a replacement for 215/40R17: the diameter differs by +5.05%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
Speedometer and odometer
With 225/45R17 on a car calibrated for 215/40R17, the speedometer reads 57.1 mph when you're really doing 60, and the odometer under-counts by 5.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 31.5 mph |
| 45 mph | 47.3 mph |
| 60 mph | 63.0 mph |
| 70 mph | 73.5 mph |
| 80 mph | 84.0 mph |
Other sizes close to 215/40R17
Questions
Can I replace 215/40R17 with 225/45R17?
225/45R17 is outside the ±3% rule as a replacement for 215/40R17: the diameter differs by +5.05%, so the speedometer, odometer and ABS calibration will be off and clearance needs checking.
What's the difference between 215/40R17 and 225/45R17?
225/45R17 is 1.20" taller and 10 mm wider; the sidewall is +0.60". At an indicated 60 mph you'd actually be doing 63.0 mph.
Will 225/45R17 fit on 215/40R17 wheels?
Both use a 17" rim, so the wheel diameter matches; check the wheel's width range for a 225 mm tire and the fender clearance.