215/55R15 vs 225/50R15
Going from one to the other changes the overall height by -1.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/55R15 | 225/50R15 | Change |
|---|---|---|---|
| Overall height | 24.3" | 23.9" | -1.9 % |
| Sidewall | 4.66" | 4.43" | -4.9 % |
| Section width | 215 mm | 225 mm | +4.7 % |
| Circumference | 76.4" | 75.0" | -1.9 % |
| Revs per mile | 830 | 845 | +1.9 % |
| Axle height | 12.16" | 11.93" | -5.8 mm |
| Approved rim width | 6–8" | 6–8.5" | overlap 6–8" |
Both are approved on a rim 6" to 8" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/55R15. Fit 225/50R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 49.1 mph | -0.9 |
| 70 mph | 68.7 mph | -1.3 |
| 90 mph | 88.3 mph | -1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,814 on the road, so it over-counts by 186. At a true 70 mph the first turns 968 times a minute, the second 986.
What drivers reported
Nobody has filed a complaint naming 215/55R15. 225/50R15 carries 1.