275/40R23 vs 295/35R23
Going from one to the other changes the overall height by -1.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/40R23 | 295/35R23 | Change |
|---|---|---|---|
| Overall height | 31.7" | 31.1" | -1.7 % |
| Sidewall | 4.33" | 4.06" | -6.1 % |
| Section width | 275 mm | 295 mm | +7.3 % |
| Circumference | 99.5" | 97.8" | -1.7 % |
| Revs per mile | 637 | 648 | +1.7 % |
| Axle height | 15.83" | 15.56" | -6.8 mm |
| Approved rim width | 7.5–10" | 8.5–11" | overlap 8.5–10" |
Both are approved on a rim 8.5" to 10" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 275/40R23. Fit 295/35R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.2 mph | -0.8 |
| 70 mph | 68.8 mph | -1.2 |
| 90 mph | 88.5 mph | -1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,832 on the road, so it over-counts by 168. At a true 70 mph the first turns 743 times a minute, the second 756.