275/70R15 vs 265/70R15
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 | 275/70R15 | 265/70R15 | Change |
|---|---|---|---|
| Overall height | 30.2" | 29.6" | -1.8 % |
| Sidewall | 7.58" | 7.30" | -3.6 % |
| Section width | 275 mm | 265 mm | -3.6 % |
| Circumference | 94.7" | 93.0" | -1.8 % |
| Revs per mile | 669 | 681 | +1.8 % |
| Axle height | 15.08" | 14.80" | -7.0 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 275/70R15. Fit 265/70R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.1 mph | -0.9 |
| 70 mph | 68.7 mph | -1.3 |
| 90 mph | 88.4 mph | -1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,817 on the road, so it over-counts by 183. At a true 70 mph the first turns 780 times a minute, the second 795.
What drivers reported
Nobody has filed a complaint naming 275/70R15. 265/70R15 carries 33.