195/50R15 vs 175/55R15
Going from one to the other changes the overall height by -0.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/50R15 | 175/55R15 | Change |
|---|---|---|---|
| Overall height | 22.7" | 22.6" | -0.4 % |
| Sidewall | 3.84" | 3.79" | -1.3 % |
| Section width | 195 mm | 175 mm | -10.3 % |
| Circumference | 71.2" | 70.9" | -0.4 % |
| Revs per mile | 889 | 893 | +0.4 % |
| Axle height | 11.34" | 11.29" | -1.3 mm |
| Approved rim width | 5.5–7" | 5–6" | overlap 5.5–6" |
Both are approved on a rim 5.5" to 6" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 195/50R15. Fit 175/55R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.9 mph | -0.1 |
| 50 mph | 49.8 mph | -0.2 |
| 70 mph | 69.7 mph | -0.3 |
| 90 mph | 89.6 mph | -0.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,957 on the road, so it over-counts by 43. At a true 70 mph the first turns 1038 times a minute, the second 1042.
What drivers reported
195/50R15 carries 6 complaints. Nobody has filed one naming 175/55R15.