185/70R13 vs 165/75R13
Going from one to the other changes the overall height by -2.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 185/70R13 | 165/75R13 | Change |
|---|---|---|---|
| Overall height | 23.2" | 22.7" | -2.0 % |
| Sidewall | 5.10" | 4.87" | -4.4 % |
| Section width | 185 mm | 165 mm | -10.8 % |
| Circumference | 72.9" | 71.5" | -2.0 % |
| Revs per mile | 869 | 887 | +2.0 % |
| Axle height | 11.60" | 11.37" | -5.8 mm |
| Approved rim width | 5–6.5" | 4.5–6" | 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 185/70R13. Fit 165/75R13 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 49.0 mph | -1.0 |
| 70 mph | 68.6 mph | -1.4 |
| 90 mph | 88.2 mph | -1.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,805 on the road, so it over-counts by 195. At a true 70 mph the first turns 1014 times a minute, the second 1035.
What drivers reported
185/70R13 carries 6 complaints. Nobody has filed one naming 165/75R13.