165/60R15 vs 155/65R15
Going from one to the other changes the overall height by +0.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/60R15 | 155/65R15 | Change |
|---|---|---|---|
| Overall height | 22.8" | 22.9" | +0.6 % |
| Sidewall | 3.90" | 3.97" | +1.8 % |
| Section width | 165 mm | 155 mm | -6.1 % |
| Circumference | 71.6" | 72.0" | +0.6 % |
| Revs per mile | 885 | 879 | -0.6 % |
| Axle height | 11.40" | 11.47" | +1.8 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 165/60R15. Fit 155/65R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.3 mph | +0.3 |
| 70 mph | 70.4 mph | +0.4 |
| 90 mph | 90.5 mph | +0.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,060 on the road, so it under-counts by 60. At a true 70 mph the first turns 1032 times a minute, the second 1026.