275/45R22 vs 255/50R22
Going from one to the other changes the overall height by +0.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 275/45R22 | 255/50R22 | Change |
|---|---|---|---|
| Overall height | 31.7" | 32.0" | +0.9 % |
| Sidewall | 4.87" | 5.02" | +3.0 % |
| Section width | 275 mm | 255 mm | -7.3 % |
| Circumference | 99.7" | 100.7" | +0.9 % |
| Revs per mile | 635 | 629 | -0.9 % |
| Axle height | 15.87" | 16.02" | +3.8 mm |
| Approved rim width | 7.5–10" | 7–9.5" | overlap 7.5–9.5" |
Both are approved on a rim 7.5" 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 275/45R22. Fit 255/50R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.3 mph | +0.3 |
| 50 mph | 50.5 mph | +0.5 |
| 70 mph | 70.7 mph | +0.7 |
| 90 mph | 90.8 mph | +0.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,093 on the road, so it under-counts by 93. At a true 70 mph the first turns 741 times a minute, the second 734.
What drivers reported
275/45R22 carries 1 complaints. Nobody has filed one naming 255/50R22.