175/60R17 vs 185/60R17
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 | 175/60R17 | 185/60R17 | Change |
|---|---|---|---|
| Overall height | 25.3" | 25.7" | +1.9 % |
| Sidewall | 4.13" | 4.37" | +5.7 % |
| Section width | 175 mm | 185 mm | +5.7 % |
| Circumference | 79.4" | 80.9" | +1.9 % |
| Revs per mile | 798 | 784 | -1.9 % |
| Axle height | 12.63" | 12.87" | +6.0 mm |
| Approved rim width | 5–6" | 5–6.5" | 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 185/60R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 50.9 mph | +0.9 |
| 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 10,187 on the road, so it under-counts by 187. At a true 70 mph the first turns 931 times a minute, the second 914.
What drivers reported
175/60R17 carries 2 complaints. Nobody has filed one naming 185/60R17.