145/65R15 vs 165/60R15
Going from one to the other changes the overall height by +1.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 145/65R15 | 165/60R15 | Change |
|---|---|---|---|
| Overall height | 22.4" | 22.8" | +1.7 % |
| Sidewall | 3.71" | 3.90" | +5.0 % |
| Section width | 145 mm | 165 mm | +13.8 % |
| Circumference | 70.4" | 71.6" | +1.7 % |
| Revs per mile | 900 | 885 | -1.7 % |
| Axle height | 11.21" | 11.40" | +4.8 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 145/65R15. Fit 165/60R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.8 mph | +0.8 |
| 70 mph | 71.2 mph | +1.2 |
| 90 mph | 91.5 mph | +1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,167 on the road, so it under-counts by 167. At a true 70 mph the first turns 1049 times a minute, the second 1032.