145/60R14 vs 125/70R14
Going from one to the other changes the overall height by +0.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 145/60R14 | 125/70R14 | Change |
|---|---|---|---|
| Overall height | 20.9" | 20.9" | +0.2 % |
| Sidewall | 3.43" | 3.44" | +0.6 % |
| Section width | 145 mm | 125 mm | -13.8 % |
| Circumference | 65.5" | 65.6" | +0.2 % |
| Revs per mile | 967 | 965 | -0.2 % |
| Axle height | 10.43" | 10.44" | +0.5 mm |
| Approved rim width | 4–5.5" | 3.5–4.5" | overlap 4–4.5" |
Both are approved on a rim 4" to 4.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 145/60R14. Fit 125/70R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.1 mph | +0.1 |
| 50 mph | 50.1 mph | +0.1 |
| 70 mph | 70.1 mph | +0.1 |
| 90 mph | 90.2 mph | +0.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,019 on the road, so it under-counts by 19. At a true 70 mph the first turns 1128 times a minute, the second 1126.
What drivers reported
Nobody has filed a complaint naming 145/60R14. 125/70R14 carries 1.