265/55R24 vs 285/50R24
Going from one to the other changes the overall height by -0.7 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/55R24 | 285/50R24 | Change |
|---|---|---|---|
| Overall height | 35.5" | 35.2" | -0.7 % |
| Sidewall | 5.74" | 5.61" | -2.2 % |
| Section width | 265 mm | 285 mm | +7.5 % |
| Circumference | 111.5" | 110.6" | -0.7 % |
| Revs per mile | 568 | 573 | +0.7 % |
| Axle height | 17.74" | 17.61" | -3.3 mm |
| Approved rim width | 7.5–9.5" | 8–10.5" | overlap 8–9.5" |
Both are approved on a rim 8" to 9.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 265/55R24. Fit 285/50R24 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.8 mph | -0.2 |
| 50 mph | 49.6 mph | -0.4 |
| 70 mph | 69.5 mph | -0.5 |
| 90 mph | 89.4 mph | -0.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,928 on the road, so it over-counts by 72. At a true 70 mph the first turns 663 times a minute, the second 668.