275/70R22 vs 265/75R22
Going from one to the other changes the overall height by +1.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/70R22 | 265/75R22 | Change |
|---|---|---|---|
| Overall height | 37.2" | 37.6" | +1.3 % |
| Sidewall | 7.58" | 7.82" | +3.2 % |
| Section width | 275 mm | 265 mm | -3.6 % |
| Circumference | 116.7" | 118.3" | +1.3 % |
| Revs per mile | 543 | 536 | -1.3 % |
| Axle height | 18.58" | 18.82" | +6.3 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 275/70R22. Fit 265/75R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.7 mph | +0.7 |
| 70 mph | 70.9 mph | +0.9 |
| 90 mph | 91.2 mph | +1.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,132 on the road, so it under-counts by 132. At a true 70 mph the first turns 633 times a minute, the second 625.