215/70R17 vs 195/75R17
Going from one to the other changes the overall height by -1.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/70R17 | 195/75R17 | Change |
|---|---|---|---|
| Overall height | 28.9" | 28.5" | -1.2 % |
| Sidewall | 5.93" | 5.76" | -2.8 % |
| Section width | 215 mm | 195 mm | -9.3 % |
| Circumference | 90.6" | 89.6" | -1.2 % |
| Revs per mile | 699 | 707 | +1.2 % |
| Axle height | 14.43" | 14.26" | -4.3 mm |
| Approved rim width | 6–8" | 5.5–7" | overlap 6–7" |
Both are approved on a rim 6" to 7" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/70R17. Fit 195/75R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.4 mph | -0.6 |
| 70 mph | 69.2 mph | -0.8 |
| 90 mph | 89.0 mph | -1.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,884 on the road, so it over-counts by 116. At a true 70 mph the first turns 816 times a minute, the second 825.