195/50R14 vs 185/55R14
Going from one to the other changes the overall height by +1.5 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/50R14 | 185/55R14 | Change |
|---|---|---|---|
| Overall height | 21.7" | 22.0" | +1.5 % |
| Sidewall | 3.84" | 4.01" | +4.4 % |
| Section width | 195 mm | 185 mm | -5.1 % |
| Circumference | 68.1" | 69.2" | +1.5 % |
| Revs per mile | 930 | 916 | -1.5 % |
| Axle height | 10.84" | 11.01" | +4.3 mm |
| Approved rim width | 5.5–7" | 5–6.5" | overlap 5.5–6.5" |
Both are approved on a rim 5.5" to 6.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 195/50R14. Fit 185/55R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.8 mph | +0.8 |
| 70 mph | 71.1 mph | +1.1 |
| 90 mph | 91.4 mph | +1.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,154 on the road, so it under-counts by 154. At a true 70 mph the first turns 1085 times a minute, the second 1069.