345/40R24 vs 335/45R24
Going from one to the other changes the overall height by +2.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 345/40R24 | 335/45R24 | Change |
|---|---|---|---|
| Overall height | 34.9" | 35.9" | +2.9 % |
| Sidewall | 5.43" | 5.94" | +9.2 % |
| Section width | 345 mm | 335 mm | -2.9 % |
| Circumference | 109.5" | 112.7" | +2.9 % |
| Revs per mile | 578 | 562 | -2.9 % |
| Axle height | 17.43" | 17.94" | +12.8 mm |
| Approved rim width | 9.5–12.5" | 9.5–12.5" | overlap 9.5–12.5" |
Both are approved on a rim 9.5" 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 345/40R24. Fit 335/45R24 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.9 mph | +0.9 |
| 50 mph | 51.4 mph | +1.4 |
| 70 mph | 72.0 mph | +2.0 |
| 90 mph | 92.6 mph | +2.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,288 on the road, so it under-counts by 288. At a true 70 mph the first turns 675 times a minute, the second 656.