215/60R15 vs 225/55R15
Going from one to the other changes the overall height by -1.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/60R15 | 225/55R15 | Change |
|---|---|---|---|
| Overall height | 25.2" | 24.7" | -1.6 % |
| Sidewall | 5.08" | 4.87" | -4.1 % |
| Section width | 215 mm | 225 mm | +4.7 % |
| Circumference | 79.0" | 77.7" | -1.6 % |
| Revs per mile | 802 | 815 | +1.6 % |
| Axle height | 12.58" | 12.37" | -5.3 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 215/60R15. Fit 225/55R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.2 mph | -0.8 |
| 70 mph | 68.8 mph | -1.2 |
| 90 mph | 88.5 mph | -1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,836 on the road, so it over-counts by 164. At a true 70 mph the first turns 935 times a minute, the second 951.
What drivers reported
215/60R15 carries 30 complaints. Nobody has filed one naming 225/55R15.