135/70R18 vs 145/65R18
Going from one to the other changes the overall height by -0.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 135/70R18 | 145/65R18 | Change |
|---|---|---|---|
| Overall height | 25.4" | 25.4" | -0.1 % |
| Sidewall | 3.72" | 3.71" | -0.3 % |
| Section width | 135 mm | 145 mm | +7.4 % |
| Circumference | 79.9" | 79.9" | -0.1 % |
| Revs per mile | 793 | 793 | +0.1 % |
| Axle height | 12.72" | 12.71" | -0.3 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 135/70R18. Fit 145/65R18 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.0 mph | -0.0 |
| 50 mph | 50.0 mph | -0.0 |
| 70 mph | 69.9 mph | -0.1 |
| 90 mph | 89.9 mph | -0.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,992 on the road, so it over-counts by 8. At a true 70 mph the first turns 925 times a minute, the second 926.
What drivers reported
135/70R18 carries 1 complaints. Nobody has filed one naming 145/65R18.