215/55R16 vs 205/55R16
Going from one to the other changes the overall height by -1.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/55R16 | 205/55R16 | Change |
|---|---|---|---|
| Overall height | 25.3" | 24.9" | -1.7 % |
| Sidewall | 4.66" | 4.44" | -4.7 % |
| Section width | 215 mm | 205 mm | -4.7 % |
| Circumference | 79.5" | 78.2" | -1.7 % |
| Revs per mile | 797 | 811 | +1.7 % |
| Axle height | 12.66" | 12.44" | -5.5 mm |
| Approved rim width | 6–8" | 5.5–7.5" | 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 215/55R16. Fit 205/55R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.1 mph | -0.9 |
| 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 9,829 on the road, so it over-counts by 171. At a true 70 mph the first turns 930 times a minute, the second 946.