265/40R24 vs 275/35R24
Going from one to the other changes the overall height by -2.4 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/40R24 | 275/35R24 | Change |
|---|---|---|---|
| Overall height | 32.3" | 31.6" | -2.4 % |
| Sidewall | 4.17" | 3.79" | -9.2 % |
| Section width | 265 mm | 275 mm | +3.8 % |
| Circumference | 101.6" | 99.2" | -2.4 % |
| Revs per mile | 624 | 639 | +2.4 % |
| Axle height | 16.17" | 15.79" | -9.8 mm |
| Approved rim width | 7.5–9.5" | 7.5–10" | overlap 7.5–9.5" |
Both are approved on a rim 7.5" to 9.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 265/40R24. Fit 275/35R24 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.3 mph | -0.7 |
| 50 mph | 48.8 mph | -1.2 |
| 70 mph | 68.3 mph | -1.7 |
| 90 mph | 87.9 mph | -2.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,763 on the road, so it over-counts by 237. At a true 70 mph the first turns 727 times a minute, the second 745.