355/25R24 vs 335/30R24
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 | 355/25R24 | 335/30R24 | Change |
|---|---|---|---|
| Overall height | 31.0" | 31.9" | +3.0 % |
| Sidewall | 3.49" | 3.96" | +13.2 % |
| Section width | 355 mm | 335 mm | -5.6 % |
| Circumference | 97.4" | 100.3" | +3.0 % |
| Revs per mile | 651 | 632 | -3.0 % |
| Axle height | 15.49" | 15.96" | +11.8 mm |
| Approved rim width | 10–13" | 9.5–12.5" | 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 355/25R24. Fit 335/30R24 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.9 mph | +0.9 |
| 50 mph | 51.5 mph | +1.5 |
| 70 mph | 72.1 mph | +2.1 |
| 90 mph | 92.7 mph | +2.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,299 on the road, so it under-counts by 299. At a true 70 mph the first turns 759 times a minute, the second 737.