165/55R14 vs 145/60R14
Going from one to the other changes the overall height by -1.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/55R14 | 145/60R14 | Change |
|---|---|---|---|
| Overall height | 21.1" | 20.9" | -1.4 % |
| Sidewall | 3.57" | 3.43" | -4.1 % |
| Section width | 165 mm | 145 mm | -12.1 % |
| Circumference | 66.4" | 65.5" | -1.4 % |
| Revs per mile | 954 | 967 | +1.4 % |
| Axle height | 10.57" | 10.43" | -3.8 mm |
| Approved rim width | 4.5–6" | 4–5.5" | 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 165/55R14. Fit 145/60R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.6 mph | -0.4 |
| 50 mph | 49.3 mph | -0.7 |
| 70 mph | 69.0 mph | -1.0 |
| 90 mph | 88.7 mph | -1.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,860 on the road, so it over-counts by 140. At a true 70 mph the first turns 1113 times a minute, the second 1128.