275/70R17 vs 285/65R17
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 | 275/70R17 | 285/65R17 | Change |
|---|---|---|---|
| Overall height | 32.2" | 31.6" | -1.8 % |
| Sidewall | 7.58" | 7.29" | -3.8 % |
| Section width | 275 mm | 285 mm | +3.6 % |
| Circumference | 101.0" | 99.2" | -1.8 % |
| Revs per mile | 627 | 639 | +1.8 % |
| Axle height | 16.08" | 15.79" | -7.3 mm |
| Approved rim width | 7.5–10" | 8–10.5" | overlap 8–10" |
Both are approved on a rim 8" to 10" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 275/70R17. Fit 285/65R17 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 | 88.4 mph | -1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,822 on the road, so it over-counts by 178. At a true 70 mph the first turns 732 times a minute, the second 745.
What drivers reported
275/70R17 carries 1 complaints. Nobody has filed one naming 285/65R17.