195/65R17 vs 185/70R17
Going from one to the other changes the overall height by +0.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 195/65R17 | 185/70R17 | Change |
|---|---|---|---|
| Overall height | 27.0" | 27.2" | +0.8 % |
| Sidewall | 4.99" | 5.10" | +2.2 % |
| Section width | 195 mm | 185 mm | -5.1 % |
| Circumference | 84.8" | 85.4" | +0.8 % |
| Revs per mile | 748 | 742 | -0.8 % |
| Axle height | 13.49" | 13.60" | +2.8 mm |
| Approved rim width | 5.5–7" | 5–6.5" | 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 195/65R17. Fit 185/70R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.4 mph | +0.4 |
| 70 mph | 70.6 mph | +0.6 |
| 90 mph | 90.7 mph | +0.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,080 on the road, so it under-counts by 80. At a true 70 mph the first turns 872 times a minute, the second 865.
What drivers reported
195/65R17 carries 2 complaints. Nobody has filed one naming 185/70R17.