205/60R15 vs 195/65R15
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 | 205/60R15 | 195/65R15 | Change |
|---|---|---|---|
| Overall height | 24.7" | 25.0" | +1.2 % |
| Sidewall | 4.84" | 4.99" | +3.0 % |
| Section width | 205 mm | 195 mm | -4.9 % |
| Circumference | 77.6" | 78.5" | +1.2 % |
| Revs per mile | 817 | 807 | -1.2 % |
| Axle height | 12.34" | 12.49" | +3.8 mm |
| Approved rim width | 5.5–7.5" | 5.5–7" | overlap 5.5–7" |
Both are approved on a rim 5.5" to 7" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 205/60R15. Fit 195/65R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.6 mph | +0.6 |
| 70 mph | 70.8 mph | +0.8 |
| 90 mph | 91.1 mph | +1.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,120 on the road, so it under-counts by 120. At a true 70 mph the first turns 953 times a minute, the second 942.