165/85R14 vs 175/85R14
Going from one to the other changes the overall height by +2.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/85R14 | 175/85R14 | Change |
|---|---|---|---|
| Overall height | 25.0" | 25.7" | +2.7 % |
| Sidewall | 5.52" | 5.86" | +6.1 % |
| Section width | 165 mm | 175 mm | +6.1 % |
| Circumference | 78.7" | 80.8" | +2.7 % |
| Revs per mile | 805 | 784 | -2.7 % |
| Axle height | 12.52" | 12.86" | +8.5 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 165/85R14. Fit 175/85R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 |
| 50 mph | 51.3 mph | +1.3 |
| 70 mph | 71.9 mph | +1.9 |
| 90 mph | 92.4 mph | +2.4 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,267 on the road, so it under-counts by 267. At a true 70 mph the first turns 940 times a minute, the second 915.