335/30R23 vs 355/25R23
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 | 335/30R23 | 355/25R23 | Change |
|---|---|---|---|
| Overall height | 30.9" | 30.0" | -3.0 % |
| Sidewall | 3.96" | 3.49" | -11.7 % |
| Section width | 335 mm | 355 mm | +6.0 % |
| Circumference | 97.1" | 94.2" | -3.0 % |
| Revs per mile | 652 | 673 | +3.0 % |
| Axle height | 15.46" | 14.99" | -11.8 mm |
| Approved rim width | 9.5–12.5" | 10–13" | overlap 10–12.5" |
Both are approved on a rim 10" to 12.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 335/30R23. Fit 355/25R23 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 761 times a minute, the second 785.