165/65R14 vs 175/65R14
Going from one to the other changes the overall height by +2.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/65R14 | 175/65R14 | Change |
|---|---|---|---|
| Overall height | 22.4" | 23.0" | +2.3 % |
| Sidewall | 4.22" | 4.48" | +6.1 % |
| Section width | 165 mm | 175 mm | +6.1 % |
| Circumference | 70.5" | 72.1" | +2.3 % |
| Revs per mile | 899 | 879 | -2.3 % |
| Axle height | 11.22" | 11.48" | +6.5 mm |
| Approved rim width | 4.5–6" | 5–6" | overlap 5–6" |
Both are approved on a rim 5" to 6" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 165/65R14. Fit 175/65R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.1 mph | +1.1 |
| 70 mph | 71.6 mph | +1.6 |
| 90 mph | 92.1 mph | +2.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,228 on the road, so it under-counts by 228. At a true 70 mph the first turns 1048 times a minute, the second 1025.