335/60R24 vs 325/60R24
Going from one to the other changes the overall height by -1.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 335/60R24 | 325/60R24 | Change |
|---|---|---|---|
| Overall height | 39.8" | 39.4" | -1.2 % |
| Sidewall | 7.91" | 7.68" | -3.0 % |
| Section width | 335 mm | 325 mm | -3.0 % |
| Circumference | 125.1" | 123.6" | -1.2 % |
| Revs per mile | 506 | 512 | +1.2 % |
| Axle height | 19.91" | 19.68" | -6.0 mm |
| Approved rim width | 9.5–12.5" | 9–12" | overlap 9.5–12" |
Both are approved on a rim 9.5" to 12" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 335/60R24. Fit 325/60R24 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.6 mph | -0.4 |
| 50 mph | 49.4 mph | -0.6 |
| 70 mph | 69.2 mph | -0.8 |
| 90 mph | 88.9 mph | -1.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,881 on the road, so it over-counts by 119. At a true 70 mph the first turns 591 times a minute, the second 598.