275/60R17 vs 285/55R17
Going from one to the other changes the overall height by -2.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/60R17 | 285/55R17 | Change |
|---|---|---|---|
| Overall height | 30.0" | 29.3" | -2.2 % |
| Sidewall | 6.50" | 6.17" | -5.0 % |
| Section width | 275 mm | 285 mm | +3.6 % |
| Circumference | 94.2" | 92.2" | -2.2 % |
| Revs per mile | 672 | 687 | +2.2 % |
| Axle height | 15.00" | 14.67" | -8.3 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 275/60R17. Fit 285/55R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 48.9 mph | -1.1 |
| 70 mph | 68.5 mph | -1.5 |
| 90 mph | 88.1 mph | -1.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,783 on the road, so it over-counts by 217. At a true 70 mph the first turns 785 times a minute, the second 802.
What drivers reported
275/60R17 carries 48 complaints. Nobody has filed one naming 285/55R17.