155/75R13 vs 135/85R13
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 | 155/75R13 | 135/85R13 | Change |
|---|---|---|---|
| Overall height | 22.2" | 22.0" | -0.5 % |
| Sidewall | 4.58" | 4.52" | -1.3 % |
| Section width | 155 mm | 135 mm | -12.9 % |
| Circumference | 69.6" | 69.2" | -0.5 % |
| Revs per mile | 910 | 915 | +0.5 % |
| Axle height | 11.08" | 11.02" | -1.5 mm |
| Approved rim width | 4–5.5" | 3.5–5" | 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 155/75R13. Fit 135/85R13 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.8 mph | -0.2 |
| 50 mph | 49.7 mph | -0.3 |
| 70 mph | 69.6 mph | -0.4 |
| 90 mph | 89.5 mph | -0.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,947 on the road, so it over-counts by 53. At a true 70 mph the first turns 1062 times a minute, the second 1068.