175/70R16 vs 185/65R16
Going from one to the other changes the overall height by -0.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 175/70R16 | 185/65R16 | Change |
|---|---|---|---|
| Overall height | 25.6" | 25.5" | -0.7 % |
| Sidewall | 4.82" | 4.73" | -1.8 % |
| Section width | 175 mm | 185 mm | +5.7 % |
| Circumference | 80.6" | 80.0" | -0.7 % |
| Revs per mile | 786 | 792 | +0.7 % |
| Axle height | 12.82" | 12.73" | -2.3 mm |
| Approved rim width | 5–6" | 5–6.5" | overlap 5–6" |
Both are approved on a rim 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 175/70R16. Fit 185/65R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.8 mph | -0.2 |
| 50 mph | 49.7 mph | -0.3 |
| 70 mph | 69.5 mph | -0.5 |
| 90 mph | 89.4 mph | -0.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,931 on the road, so it over-counts by 69. At a true 70 mph the first turns 917 times a minute, the second 924.
What drivers reported
Nobody has filed a complaint naming 175/70R16. 185/65R16 carries 2.