295/35R23 vs 275/40R23
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 | 295/35R23 | 275/40R23 | Change |
|---|---|---|---|
| Overall height | 31.1" | 31.7" | +1.7 % |
| Sidewall | 4.06" | 4.33" | +6.5 % |
| Section width | 295 mm | 275 mm | -6.8 % |
| Circumference | 97.8" | 99.5" | +1.7 % |
| Revs per mile | 648 | 637 | -1.7 % |
| Axle height | 15.56" | 15.83" | +6.8 mm |
| Approved rim width | 8.5–11" | 7.5–10" | 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 295/35R23. Fit 275/40R23 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.2 mph | +1.2 |
| 90 mph | 91.5 mph | +1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,171 on the road, so it under-counts by 171. At a true 70 mph the first turns 756 times a minute, the second 743.