175/75R15 vs 195/65R15
Going from one to the other changes the overall height by -1.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 175/75R15 | 195/65R15 | Change |
|---|---|---|---|
| Overall height | 25.3" | 25.0" | -1.4 % |
| Sidewall | 5.17" | 4.99" | -3.4 % |
| Section width | 175 mm | 195 mm | +11.4 % |
| Circumference | 79.6" | 78.5" | -1.4 % |
| Revs per mile | 796 | 807 | +1.4 % |
| Axle height | 12.67" | 12.49" | -4.5 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 175/75R15. Fit 195/65R15 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 | 69.0 mph | -1.0 |
| 90 mph | 88.7 mph | -1.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,860 on the road, so it over-counts by 140. At a true 70 mph the first turns 929 times a minute, the second 942.
What drivers reported
Nobody has filed a complaint naming 175/75R15. 195/65R15 carries 145.