135/85R13 vs 155/75R13
Going from one to the other changes the overall height by +0.5 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 135/85R13 | 155/75R13 | Change |
|---|---|---|---|
| Overall height | 22.0" | 22.2" | +0.5 % |
| Sidewall | 4.52" | 4.58" | +1.3 % |
| Section width | 135 mm | 155 mm | +14.8 % |
| Circumference | 69.2" | 69.6" | +0.5 % |
| Revs per mile | 915 | 910 | -0.5 % |
| Axle height | 11.02" | 11.08" | +1.5 mm |
| Approved rim width | 3.5–5" | 4–5.5" | overlap 4–5" |
Both are approved on a rim 4" to 5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 135/85R13. Fit 155/75R13 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.2 mph | +0.2 |
| 50 mph | 50.3 mph | +0.3 |
| 70 mph | 70.4 mph | +0.4 |
| 90 mph | 90.5 mph | +0.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,054 on the road, so it under-counts by 54. At a true 70 mph the first turns 1068 times a minute, the second 1062.