195/70R17 vs 175/75R17
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 | 195/70R17 | 175/75R17 | Change |
|---|---|---|---|
| Overall height | 27.7" | 27.3" | -1.5 % |
| Sidewall | 5.37" | 5.17" | -3.8 % |
| Section width | 195 mm | 175 mm | -10.3 % |
| Circumference | 87.2" | 85.9" | -1.5 % |
| Revs per mile | 727 | 738 | +1.5 % |
| Axle height | 13.87" | 13.67" | -5.3 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 195/70R17. Fit 175/75R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.6 mph | -0.4 |
| 50 mph | 49.3 mph | -0.7 |
| 70 mph | 69.0 mph | -1.0 |
| 90 mph | 88.7 mph | -1.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,851 on the road, so it over-counts by 149. At a true 70 mph the first turns 848 times a minute, the second 861.