275/45R16 vs 295/40R16
Going from one to the other changes the overall height by -1.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/45R16 | 295/40R16 | Change |
|---|---|---|---|
| Overall height | 25.7" | 25.3" | -1.8 % |
| Sidewall | 4.87" | 4.65" | -4.6 % |
| Section width | 275 mm | 295 mm | +7.3 % |
| Circumference | 80.9" | 79.5" | -1.8 % |
| Revs per mile | 783 | 797 | +1.8 % |
| Axle height | 12.87" | 12.65" | -5.8 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 275/45R16. Fit 295/40R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.1 mph | -0.9 |
| 70 mph | 68.8 mph | -1.2 |
| 90 mph | 88.4 mph | -1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,824 on the road, so it over-counts by 176. At a true 70 mph the first turns 914 times a minute, the second 930.