195/65R15 vs 175/70R15
Going from one to the other changes the overall height by -1.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/65R15 | 175/70R15 | Change |
|---|---|---|---|
| Overall height | 25.0" | 24.6" | -1.3 % |
| Sidewall | 4.99" | 4.82" | -3.4 % |
| Section width | 195 mm | 175 mm | -10.3 % |
| Circumference | 78.5" | 77.4" | -1.3 % |
| Revs per mile | 807 | 818 | +1.3 % |
| Axle height | 12.49" | 12.32" | -4.3 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 195/65R15. Fit 175/70R15 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 | 69.1 mph | -0.9 |
| 90 mph | 88.8 mph | -1.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,866 on the road, so it over-counts by 134. At a true 70 mph the first turns 942 times a minute, the second 955.