265/65R20 vs 275/60R20
Going from one to the other changes the overall height by -1.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/65R20 | 275/60R20 | Change |
|---|---|---|---|
| Overall height | 33.6" | 33.0" | -1.7 % |
| Sidewall | 6.78" | 6.50" | -4.2 % |
| Section width | 265 mm | 275 mm | +3.8 % |
| Circumference | 105.4" | 103.6" | -1.7 % |
| Revs per mile | 601 | 611 | +1.7 % |
| Axle height | 16.78" | 16.50" | -7.3 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 265/65R20. Fit 275/60R20 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 | 68.8 mph | -1.2 |
| 90 mph | 88.5 mph | -1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,830 on the road, so it over-counts by 170. At a true 70 mph the first turns 701 times a minute, the second 713.
What drivers reported
Nobody has filed a complaint naming 265/65R20. 275/60R20 carries 27.