135/65R16 vs 125/70R16
Going from one to the other changes the overall height by -0.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 135/65R16 | 125/70R16 | Change |
|---|---|---|---|
| Overall height | 22.9" | 22.9" | -0.1 % |
| Sidewall | 3.45" | 3.44" | -0.3 % |
| Section width | 135 mm | 125 mm | -7.4 % |
| Circumference | 72.0" | 71.9" | -0.1 % |
| Revs per mile | 880 | 881 | +0.1 % |
| Axle height | 11.45" | 11.44" | -0.3 mm |
| Approved rim width | 3.5–5" | 3.5–4.5" | overlap 3.5–4.5" |
Both are approved on a rim 3.5" 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 135/65R16. Fit 125/70R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.0 mph | -0.0 |
| 50 mph | 50.0 mph | -0.0 |
| 70 mph | 69.9 mph | -0.1 |
| 90 mph | 89.9 mph | -0.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,991 on the road, so it over-counts by 9. At a true 70 mph the first turns 1027 times a minute, the second 1028.
What drivers reported
Nobody has filed a complaint naming 135/65R16. 125/70R16 carries 10.