165/60R14 vs 185/55R14
Going from one to the other changes the overall height by +1.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/60R14 | 185/55R14 | Change |
|---|---|---|---|
| Overall height | 21.8" | 22.0" | +1.0 % |
| Sidewall | 3.90" | 4.01" | +2.8 % |
| Section width | 165 mm | 185 mm | +12.1 % |
| Circumference | 68.5" | 69.2" | +1.0 % |
| Revs per mile | 925 | 916 | -1.0 % |
| Axle height | 10.90" | 11.01" | +2.8 mm |
| Approved rim width | 4.5–6" | 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 165/60R14. Fit 185/55R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.3 mph | +0.3 |
| 50 mph | 50.5 mph | +0.5 |
| 70 mph | 70.7 mph | +0.7 |
| 90 mph | 90.9 mph | +0.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,099 on the road, so it under-counts by 99. At a true 70 mph the first turns 1080 times a minute, the second 1069.