225/50R15 vs 215/55R15
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 | 225/50R15 | 215/55R15 | Change |
|---|---|---|---|
| Overall height | 23.9" | 24.3" | +1.9 % |
| Sidewall | 4.43" | 4.66" | +5.1 % |
| Section width | 225 mm | 215 mm | -4.4 % |
| Circumference | 75.0" | 76.4" | +1.9 % |
| Revs per mile | 845 | 830 | -1.9 % |
| Axle height | 11.93" | 12.16" | +5.8 mm |
| Approved rim width | 6–8.5" | 6–8" | 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 225/50R15. Fit 215/55R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.3 mph | +1.3 |
| 90 mph | 91.7 mph | +1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,190 on the road, so it under-counts by 190. At a true 70 mph the first turns 986 times a minute, the second 968.
What drivers reported
225/50R15 carries 1 complaints. Nobody has filed one naming 215/55R15.