155/85R14 vs 175/70R14
Going from one to the other changes the overall height by -3.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 155/85R14 | 175/70R14 | Change |
|---|---|---|---|
| Overall height | 24.4" | 23.6" | -3.0 % |
| Sidewall | 5.19" | 4.82" | -7.0 % |
| Section width | 155 mm | 175 mm | +12.9 % |
| Circumference | 76.6" | 74.3" | -3.0 % |
| Revs per mile | 827 | 853 | +3.0 % |
| Axle height | 12.19" | 11.82" | -9.3 mm |
| Approved rim width | 4–5.5" | 5–6" | overlap 5–5.5" |
Both are approved on a rim 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 155/85R14. Fit 175/70R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.1 mph | -0.9 |
| 50 mph | 48.5 mph | -1.5 |
| 70 mph | 67.9 mph | -2.1 |
| 90 mph | 87.3 mph | -2.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,701 on the road, so it over-counts by 299. At a true 70 mph the first turns 965 times a minute, the second 995.
What drivers reported
Nobody has filed a complaint naming 155/85R14. 175/70R14 carries 1.