275/60R17 vs 265/65R17
Going from one to the other changes the overall height by +1.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/60R17 | 265/65R17 | Change |
|---|---|---|---|
| Overall height | 30.0" | 30.6" | +1.9 % |
| Sidewall | 6.50" | 6.78" | +4.4 % |
| Section width | 275 mm | 265 mm | -3.6 % |
| Circumference | 94.2" | 96.0" | +1.9 % |
| Revs per mile | 672 | 660 | -1.9 % |
| Axle height | 15.00" | 15.28" | +7.3 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 275/60R17. Fit 265/65R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.0 mph | +1.0 |
| 70 mph | 71.3 mph | +1.3 |
| 90 mph | 91.7 mph | +1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,190 on the road, so it under-counts by 190. At a true 70 mph the first turns 785 times a minute, the second 770.