225/50R15 vs 235/45R15
Going from one to the other changes the overall height by -2.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/50R15 | 235/45R15 | Change |
|---|---|---|---|
| Overall height | 23.9" | 23.3" | -2.2 % |
| Sidewall | 4.43" | 4.16" | -6.0 % |
| Section width | 225 mm | 235 mm | +4.4 % |
| Circumference | 75.0" | 73.3" | -2.2 % |
| Revs per mile | 845 | 865 | +2.2 % |
| Axle height | 11.93" | 11.66" | -6.8 mm |
| Approved rim width | 6–8.5" | 6.5–8.5" | overlap 6.5–8.5" |
Both are approved on a rim 6.5" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 225/50R15. Fit 235/45R15 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 9,777 on the road, so it over-counts by 223. At a true 70 mph the first turns 986 times a minute, the second 1009.
What drivers reported
225/50R15 carries 1 complaints. Nobody has filed one naming 235/45R15.