265/45R23 vs 275/45R23
Going from one to the other changes the overall height by +1.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/45R23 | 275/45R23 | Change |
|---|---|---|---|
| Overall height | 32.4" | 32.7" | +1.1 % |
| Sidewall | 4.69" | 4.87" | +3.8 % |
| Section width | 265 mm | 275 mm | +3.8 % |
| Circumference | 101.8" | 102.9" | +1.1 % |
| Revs per mile | 623 | 616 | -1.1 % |
| Axle height | 16.19" | 16.37" | +4.5 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 265/45R23. Fit 275/45R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.3 mph | +0.3 |
| 50 mph | 50.5 mph | +0.5 |
| 70 mph | 70.8 mph | +0.8 |
| 90 mph | 91.0 mph | +1.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,109 on the road, so it under-counts by 109. At a true 70 mph the first turns 726 times a minute, the second 719.