165/75R14 vs 175/75R14
Going from one to the other changes the overall height by +2.5 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/75R14 | 175/75R14 | Change |
|---|---|---|---|
| Overall height | 23.7" | 24.3" | +2.5 % |
| Sidewall | 4.87" | 5.17" | +6.1 % |
| Section width | 165 mm | 175 mm | +6.1 % |
| Circumference | 74.6" | 76.4" | +2.5 % |
| Revs per mile | 849 | 829 | -2.5 % |
| Axle height | 11.87" | 12.17" | +7.5 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 165/75R14. Fit 175/75R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.2 mph | +1.2 |
| 70 mph | 71.7 mph | +1.7 |
| 90 mph | 92.2 mph | +2.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,249 on the road, so it under-counts by 249. At a true 70 mph the first turns 991 times a minute, the second 967.