195/85R19 vs 195/80R19
Going from one to the other changes the overall height by -2.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/85R19 | 195/80R19 | Change |
|---|---|---|---|
| Overall height | 32.1" | 31.3" | -2.4 % |
| Sidewall | 6.53" | 6.14" | -5.9 % |
| Section width | 195 mm | 195 mm | 0.0 % |
| Circumference | 100.7" | 98.3" | -2.4 % |
| Revs per mile | 629 | 645 | +2.4 % |
| Axle height | 16.03" | 15.64" | -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 195/85R19. Fit 195/80R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.3 mph | -0.7 |
| 50 mph | 48.8 mph | -1.2 |
| 70 mph | 68.3 mph | -1.7 |
| 90 mph | 87.8 mph | -2.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,760 on the road, so it over-counts by 240. At a true 70 mph the first turns 734 times a minute, the second 752.