195/50R19 vs 195/45R19
Going from one to the other changes the overall height by -2.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/50R19 | 195/45R19 | Change |
|---|---|---|---|
| Overall height | 26.7" | 25.9" | -2.9 % |
| Sidewall | 3.84" | 3.45" | -10.0 % |
| Section width | 195 mm | 195 mm | 0.0 % |
| Circumference | 83.8" | 81.4" | -2.9 % |
| Revs per mile | 756 | 778 | +2.9 % |
| Axle height | 13.34" | 12.95" | -9.8 mm |
| Approved rim width | 5.5–7" | 5.5–7" | overlap 5.5–7" |
Both are approved on a rim 5.5" to 7" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 195/50R19. Fit 195/45R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.1 mph | -0.9 |
| 50 mph | 48.6 mph | -1.4 |
| 70 mph | 68.0 mph | -2.0 |
| 90 mph | 87.4 mph | -2.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,712 on the road, so it over-counts by 288. At a true 70 mph the first turns 882 times a minute, the second 908.