265/75R17 vs 275/75R17
Going from one to the other changes the overall height by +1.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/75R17 | 275/75R17 | Change |
|---|---|---|---|
| Overall height | 32.6" | 33.2" | +1.8 % |
| Sidewall | 7.82" | 8.12" | +3.8 % |
| Section width | 265 mm | 275 mm | +3.8 % |
| Circumference | 102.6" | 104.4" | +1.8 % |
| Revs per mile | 618 | 607 | -1.8 % |
| Axle height | 16.32" | 16.62" | +7.5 mm |
| Approved rim width | 7.5–9.5" | 7.5–10" | overlap 7.5–9.5" |
Both are approved on a rim 7.5" to 9.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 265/75R17. Fit 275/75R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.3 mph | +1.3 |
| 90 mph | 91.6 mph | +1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,181 on the road, so it under-counts by 181. At a true 70 mph the first turns 721 times a minute, the second 708.