285/50R24 vs 275/55R24
Going from one to the other changes the overall height by +2.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 285/50R24 | 275/55R24 | Change |
|---|---|---|---|
| Overall height | 35.2" | 35.9" | +2.0 % |
| Sidewall | 5.61" | 5.95" | +6.1 % |
| Section width | 285 mm | 275 mm | -3.5 % |
| Circumference | 110.6" | 112.8" | +2.0 % |
| Revs per mile | 573 | 562 | -2.0 % |
| Axle height | 17.61" | 17.95" | +8.8 mm |
| Approved rim width | 8–10.5" | 7.5–10" | overlap 8–10" |
Both are approved on a rim 8" to 10" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 285/50R24. Fit 275/55R24 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.0 mph | +1.0 |
| 70 mph | 71.4 mph | +1.4 |
| 90 mph | 91.8 mph | +1.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,196 on the road, so it under-counts by 196. At a true 70 mph the first turns 668 times a minute, the second 655.