175/60R17 vs 175/55R17
Going from one to the other changes the overall height by -2.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 175/60R17 | 175/55R17 | Change |
|---|---|---|---|
| Overall height | 25.3" | 24.6" | -2.7 % |
| Sidewall | 4.13" | 3.79" | -8.3 % |
| Section width | 175 mm | 175 mm | 0.0 % |
| Circumference | 79.4" | 77.2" | -2.7 % |
| Revs per mile | 798 | 821 | +2.7 % |
| Axle height | 12.63" | 12.29" | -8.8 mm |
| Approved rim width | 5–6" | 5–6" | overlap 5–6" |
Both are approved on a rim 5" to 6" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 175/60R17. Fit 175/55R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.2 mph | -0.8 |
| 50 mph | 48.6 mph | -1.4 |
| 70 mph | 68.1 mph | -1.9 |
| 90 mph | 87.5 mph | -2.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,727 on the road, so it over-counts by 273. At a true 70 mph the first turns 931 times a minute, the second 957.
What drivers reported
175/60R17 carries 2 complaints. Nobody has filed one naming 175/55R17.