225/40R19 vs 205/45R19
Going from one to the other changes the overall height by +0.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/40R19 | 205/45R19 | Change |
|---|---|---|---|
| Overall height | 26.1" | 26.3" | +0.7 % |
| Sidewall | 3.54" | 3.63" | +2.5 % |
| Section width | 225 mm | 205 mm | -8.9 % |
| Circumference | 82.0" | 82.5" | +0.7 % |
| Revs per mile | 773 | 768 | -0.7 % |
| Axle height | 13.04" | 13.13" | +2.3 mm |
| Approved rim width | 6–8.5" | 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 225/40R19. Fit 205/45R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.3 mph | +0.3 |
| 70 mph | 70.5 mph | +0.5 |
| 90 mph | 90.6 mph | +0.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,068 on the road, so it under-counts by 68. At a true 70 mph the first turns 902 times a minute, the second 896.
What drivers reported
225/40R19 carries 2 complaints. Nobody has filed one naming 205/45R19.