175/70R15 vs 195/60R15
Going from one to the other changes the overall height by -1.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 175/70R15 | 195/60R15 | Change |
|---|---|---|---|
| Overall height | 24.6" | 24.2" | -1.8 % |
| Sidewall | 4.82" | 4.61" | -4.5 % |
| Section width | 175 mm | 195 mm | +11.4 % |
| Circumference | 77.4" | 76.1" | -1.8 % |
| Revs per mile | 818 | 833 | +1.8 % |
| Axle height | 12.32" | 12.11" | -5.5 mm |
| Approved rim width | 5–6" | 5.5–7" | 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 175/70R15. Fit 195/60R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.1 mph | -0.9 |
| 70 mph | 68.8 mph | -1.2 |
| 90 mph | 88.4 mph | -1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,824 on the road, so it over-counts by 176. At a true 70 mph the first turns 955 times a minute, the second 972.