285/30R19 vs 275/30R19
Going from one to the other changes the overall height by -0.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 285/30R19 | 275/30R19 | Change |
|---|---|---|---|
| Overall height | 25.7" | 25.5" | -0.9 % |
| Sidewall | 3.37" | 3.25" | -3.5 % |
| Section width | 285 mm | 275 mm | -3.5 % |
| Circumference | 80.8" | 80.1" | -0.9 % |
| Revs per mile | 784 | 791 | +0.9 % |
| Axle height | 12.87" | 12.75" | -3.0 mm |
| Approved rim width | 8–10.5" | 7.5–10" | overlap 8–10" |
Both are approved on a rim 8" to 10" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 285/30R19. Fit 275/30R19 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.5 mph | -0.5 |
| 70 mph | 69.4 mph | -0.6 |
| 90 mph | 89.2 mph | -0.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,908 on the road, so it over-counts by 92. At a true 70 mph the first turns 914 times a minute, the second 923.
What drivers reported
285/30R19 carries 1 complaints. Nobody has filed one naming 275/30R19.