205/45R19 vs 215/40R19
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 | 205/45R19 | 215/40R19 | Change |
|---|---|---|---|
| Overall height | 26.3" | 25.8" | -1.9 % |
| Sidewall | 3.63" | 3.39" | -6.8 % |
| Section width | 205 mm | 215 mm | +4.9 % |
| Circumference | 82.5" | 81.0" | -1.9 % |
| Revs per mile | 768 | 783 | +1.9 % |
| Axle height | 13.13" | 12.89" | -6.3 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 205/45R19. Fit 215/40R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 49.1 mph | -0.9 |
| 70 mph | 68.7 mph | -1.3 |
| 90 mph | 88.3 mph | -1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,813 on the road, so it over-counts by 187. At a true 70 mph the first turns 896 times a minute, the second 913.