215/50R14 vs 235/45R14
Going from one to the other changes the overall height by -0.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/50R14 | 235/45R14 | Change |
|---|---|---|---|
| Overall height | 22.5" | 22.3" | -0.6 % |
| Sidewall | 4.23" | 4.16" | -1.6 % |
| Section width | 215 mm | 235 mm | +9.3 % |
| Circumference | 70.6" | 70.1" | -0.6 % |
| Revs per mile | 898 | 903 | +0.6 % |
| Axle height | 11.23" | 11.16" | -1.8 mm |
| Approved rim width | 6–8" | 6.5–8.5" | overlap 6.5–8" |
Both are approved on a rim 6.5" to 8" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/50R14. Fit 235/45R14 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.8 mph | -0.2 |
| 50 mph | 49.7 mph | -0.3 |
| 70 mph | 69.6 mph | -0.4 |
| 90 mph | 89.4 mph | -0.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,939 on the road, so it over-counts by 61. At a true 70 mph the first turns 1047 times a minute, the second 1054.