195/65R15 vs 175/75R15
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 | 195/65R15 | 175/75R15 | Change |
|---|---|---|---|
| Overall height | 25.0" | 25.3" | +1.4 % |
| Sidewall | 4.99" | 5.17" | +3.6 % |
| Section width | 195 mm | 175 mm | -10.3 % |
| Circumference | 78.5" | 79.6" | +1.4 % |
| Revs per mile | 807 | 796 | -1.4 % |
| Axle height | 12.49" | 12.67" | +4.5 mm |
| Approved rim width | 5.5–7" | 5–6" | 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 195/65R15. Fit 175/75R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.7 mph | +0.7 |
| 70 mph | 71.0 mph | +1.0 |
| 90 mph | 91.3 mph | +1.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,142 on the road, so it under-counts by 142. At a true 70 mph the first turns 942 times a minute, the second 929.
What drivers reported
195/65R15 carries 145 complaints. Nobody has filed one naming 175/75R15.