145/70R13 vs 165/60R13
Going from one to the other changes the overall height by -0.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 145/70R13 | 165/60R13 | Change |
|---|---|---|---|
| Overall height | 21.0" | 20.8" | -0.9 % |
| Sidewall | 4.00" | 3.90" | -2.5 % |
| Section width | 145 mm | 165 mm | +13.8 % |
| Circumference | 65.9" | 65.3" | -0.9 % |
| Revs per mile | 961 | 970 | +0.9 % |
| Axle height | 10.50" | 10.40" | -2.5 mm |
| Approved rim width | 4–5.5" | 4.5–6" | overlap 4.5–5.5" |
Both are approved on a rim 4.5" to 5.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 145/70R13. Fit 165/60R13 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.5 mph | -0.5 |
| 70 mph | 69.3 mph | -0.7 |
| 90 mph | 89.2 mph | -0.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,906 on the road, so it over-counts by 94. At a true 70 mph the first turns 1121 times a minute, the second 1131.