205/65R16 vs 185/75R16
Going from one to the other changes the overall height by +1.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 205/65R16 | 185/75R16 | Change |
|---|---|---|---|
| Overall height | 26.5" | 26.9" | +1.6 % |
| Sidewall | 5.25" | 5.46" | +4.1 % |
| Section width | 205 mm | 185 mm | -9.8 % |
| Circumference | 83.2" | 84.6" | +1.6 % |
| Revs per mile | 761 | 749 | -1.6 % |
| Axle height | 13.25" | 13.46" | +5.5 mm |
| Approved rim width | 5.5–7.5" | 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 205/65R16. Fit 185/75R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.8 mph | +0.8 |
| 70 mph | 71.1 mph | +1.1 |
| 90 mph | 91.5 mph | +1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,163 on the road, so it under-counts by 163. At a true 70 mph the first turns 888 times a minute, the second 874.
What drivers reported
205/65R16 carries 22 complaints. Nobody has filed one naming 185/75R16.