275/50R22 vs 285/45R22
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 | 275/50R22 | 285/45R22 | Change |
|---|---|---|---|
| Overall height | 32.8" | 32.1" | -2.2 % |
| Sidewall | 5.41" | 5.05" | -6.7 % |
| Section width | 275 mm | 285 mm | +3.6 % |
| Circumference | 103.1" | 100.8" | -2.2 % |
| Revs per mile | 614 | 628 | +2.2 % |
| Axle height | 16.41" | 16.05" | -9.3 mm |
| Approved rim width | 7.5–10" | 8–10.5" | 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 275/50R22. Fit 285/45R22 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 9,778 on the road, so it over-counts by 222. At a true 70 mph the first turns 717 times a minute, the second 733.