185/55R15 vs 165/60R15
Going from one to the other changes the overall height by -0.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 185/55R15 | 165/60R15 | Change |
|---|---|---|---|
| Overall height | 23.0" | 22.8" | -0.9 % |
| Sidewall | 4.01" | 3.90" | -2.7 % |
| Section width | 185 mm | 165 mm | -10.8 % |
| Circumference | 72.3" | 71.6" | -0.9 % |
| Revs per mile | 876 | 885 | +0.9 % |
| Axle height | 11.51" | 11.40" | -2.8 mm |
| Approved rim width | 5–6.5" | 4.5–6" | 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 185/55R15. Fit 165/60R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.5 mph | -0.5 |
| 70 mph | 69.3 mph | -0.7 |
| 90 mph | 89.2 mph | -0.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,906 on the road, so it over-counts by 94. At a true 70 mph the first turns 1022 times a minute, the second 1032.
What drivers reported
185/55R15 carries 3 complaints. Nobody has filed one naming 165/60R15.