205/55R20 vs 215/50R20
Going from one to the other changes the overall height by -1.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 205/55R20 | 215/50R20 | Change |
|---|---|---|---|
| Overall height | 28.9" | 28.5" | -1.4 % |
| Sidewall | 4.44" | 4.23" | -4.7 % |
| Section width | 205 mm | 215 mm | +4.9 % |
| Circumference | 90.7" | 89.4" | -1.4 % |
| Revs per mile | 698 | 709 | +1.4 % |
| Axle height | 14.44" | 14.23" | -5.3 mm |
| Approved rim width | 5.5–7.5" | 6–8" | overlap 6–7.5" |
Both are approved on a rim 6" to 7.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 205/55R20. Fit 215/50R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.6 mph | -0.4 |
| 50 mph | 49.3 mph | -0.7 |
| 70 mph | 69.0 mph | -1.0 |
| 90 mph | 88.7 mph | -1.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,857 on the road, so it over-counts by 143. At a true 70 mph the first turns 815 times a minute, the second 827.
What drivers reported
Nobody has filed a complaint naming 205/55R20. 215/50R20 carries 1.