275/35R23 vs 265/35R23
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 | 275/35R23 | 265/35R23 | Change |
|---|---|---|---|
| Overall height | 30.6" | 30.3" | -0.9 % |
| Sidewall | 3.79" | 3.65" | -3.6 % |
| Section width | 275 mm | 265 mm | -3.6 % |
| Circumference | 96.1" | 95.2" | -0.9 % |
| Revs per mile | 660 | 666 | +0.9 % |
| Axle height | 15.29" | 15.15" | -3.5 mm |
| Approved rim width | 7.5–10" | 7.5–9.5" | 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 275/35R23. Fit 265/35R23 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 9,910 on the road, so it over-counts by 90. At a true 70 mph the first turns 769 times a minute, the second 776.