225/50R19 vs 215/55R19
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 | 225/50R19 | 215/55R19 | Change |
|---|---|---|---|
| Overall height | 27.9" | 28.3" | +1.6 % |
| Sidewall | 4.43" | 4.66" | +5.1 % |
| Section width | 225 mm | 215 mm | -4.4 % |
| Circumference | 87.5" | 88.9" | +1.6 % |
| Revs per mile | 724 | 712 | -1.6 % |
| Axle height | 13.93" | 14.16" | +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 225/50R19. Fit 215/55R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.8 mph | +0.8 |
| 70 mph | 71.1 mph | +1.1 |
| 90 mph | 91.5 mph | +1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,163 on the road, so it under-counts by 163. At a true 70 mph the first turns 845 times a minute, the second 831.