295/75R22.5 vs 285/80R22.5
Going from one to the other changes the overall height by +1.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 295/75R22.5 | 285/80R22.5 | Change |
|---|---|---|---|
| Overall height | 39.9" | 40.5" | +1.3 % |
| Sidewall | 8.71" | 8.98" | +3.1 % |
| Section width | 295 mm | 285 mm | -3.4 % |
| Circumference | 125.4" | 127.1" | +1.3 % |
| Revs per mile | 505 | 499 | -1.3 % |
| Axle height | 19.96" | 20.23" | +6.8 mm |
| Approved rim width | 8.5–11" | 8–10.5" | overlap 8.5–10.5" |
Both are approved on a rim 8.5" to 10.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 295/75R22.5. Fit 285/80R22.5 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.7 mph | +0.7 |
| 70 mph | 70.9 mph | +0.9 |
| 90 mph | 91.2 mph | +1.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,133 on the road, so it under-counts by 133. At a true 70 mph the first turns 589 times a minute, the second 582.
What drivers reported
295/75R22.5 carries 16 complaints. Nobody has filed one naming 285/80R22.5.