265/75R15 vs 275/70R15
Going from one to the other changes the overall height by -1.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/75R15 | 275/70R15 | Change |
|---|---|---|---|
| Overall height | 30.6" | 30.2" | -1.6 % |
| Sidewall | 7.82" | 7.58" | -3.1 % |
| Section width | 265 mm | 275 mm | +3.8 % |
| Circumference | 96.3" | 94.7" | -1.6 % |
| Revs per mile | 658 | 669 | +1.6 % |
| Axle height | 15.32" | 15.08" | -6.3 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 265/75R15. Fit 275/70R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.2 mph | -0.8 |
| 70 mph | 68.9 mph | -1.1 |
| 90 mph | 88.6 mph | -1.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,839 on the road, so it over-counts by 161. At a true 70 mph the first turns 768 times a minute, the second 780.
What drivers reported
265/75R15 carries 11 complaints. Nobody has filed one naming 275/70R15.