185/65R15 vs 195/60R15
Going from one to the other changes the overall height by -1.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 185/65R15 | 195/60R15 | Change |
|---|---|---|---|
| Overall height | 24.5" | 24.2" | -1.0 % |
| Sidewall | 4.73" | 4.61" | -2.7 % |
| Section width | 185 mm | 195 mm | +5.4 % |
| Circumference | 76.9" | 76.1" | -1.0 % |
| Revs per mile | 824 | 833 | +1.0 % |
| Axle height | 12.23" | 12.11" | -3.3 mm |
| Approved rim width | 5–6.5" | 5.5–7" | overlap 5.5–6.5" |
Both are approved on a rim 5.5" to 6.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 185/65R15. Fit 195/60R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.5 mph | -0.5 |
| 70 mph | 69.3 mph | -0.7 |
| 90 mph | 89.1 mph | -0.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,895 on the road, so it over-counts by 105. At a true 70 mph the first turns 962 times a minute, the second 972.