265/75R22.5 vs 255/80R22.5
Going from one to the other changes the overall height by +1.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/75R22.5 | 255/80R22.5 | Change |
|---|---|---|---|
| Overall height | 38.1" | 38.6" | +1.1 % |
| Sidewall | 7.82" | 8.03" | +2.6 % |
| Section width | 265 mm | 255 mm | -3.8 % |
| Circumference | 119.9" | 121.1" | +1.1 % |
| Revs per mile | 529 | 523 | -1.1 % |
| Axle height | 19.07" | 19.28" | +5.3 mm |
| Approved rim width | 7.5–9.5" | 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 265/75R22.5. Fit 255/80R22.5 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 | 70.8 mph | +0.8 |
| 90 mph | 91.0 mph | +1.0 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,108 on the road, so it under-counts by 108. At a true 70 mph the first turns 617 times a minute, the second 610.
What drivers reported
Nobody has filed a complaint naming 265/75R22.5. 255/80R22.5 carries 42.