155/75R13 vs 175/70R13
Going from one to the other changes the overall height by +2.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 155/75R13 | 175/70R13 | Change |
|---|---|---|---|
| Overall height | 22.2" | 22.6" | +2.2 % |
| Sidewall | 4.58" | 4.82" | +5.4 % |
| Section width | 155 mm | 175 mm | +12.9 % |
| Circumference | 69.6" | 71.1" | +2.2 % |
| Revs per mile | 910 | 891 | -2.2 % |
| Axle height | 11.08" | 11.32" | +6.3 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 155/75R13. Fit 175/70R13 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 | 92.0 mph | +2.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,222 on the road, so it under-counts by 222. At a true 70 mph the first turns 1062 times a minute, the second 1039.
What drivers reported
Nobody has filed a complaint naming 155/75R13. 175/70R13 carries 56.