215/45R16 vs 225/40R16
Going from one to the other changes the overall height by -2.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/45R16 | 225/40R16 | Change |
|---|---|---|---|
| Overall height | 23.6" | 23.1" | -2.3 % |
| Sidewall | 3.81" | 3.54" | -7.0 % |
| Section width | 215 mm | 225 mm | +4.7 % |
| Circumference | 74.2" | 72.5" | -2.3 % |
| Revs per mile | 854 | 874 | +2.3 % |
| Axle height | 11.81" | 11.54" | -6.8 mm |
| Approved rim width | 6–8" | 6–8.5" | overlap 6–8" |
Both are approved on a rim 6" to 8" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/45R16. Fit 225/40R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.3 mph | -0.7 |
| 50 mph | 48.9 mph | -1.1 |
| 70 mph | 68.4 mph | -1.6 |
| 90 mph | 88.0 mph | -2.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,775 on the road, so it over-counts by 225. At a true 70 mph the first turns 996 times a minute, the second 1019.
What drivers reported
215/45R16 carries 3 complaints. Nobody has filed one naming 225/40R16.