275/75R24.5 vs 265/80R24.5
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 | 275/75R24.5 | 265/80R24.5 | Change |
|---|---|---|---|
| Overall height | 40.7" | 41.2" | +1.1 % |
| Sidewall | 8.12" | 8.35" | +2.8 % |
| Section width | 275 mm | 265 mm | -3.6 % |
| Circumference | 128.0" | 129.4" | +1.1 % |
| Revs per mile | 495 | 490 | -1.1 % |
| Axle height | 20.37" | 20.60" | +5.8 mm |
| Approved rim width | 7.5–10" | 7.5–9.5" | 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 275/75R24.5. Fit 265/80R24.5 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.3 mph | +0.3 |
| 50 mph | 50.6 mph | +0.6 |
| 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 10,111 on the road, so it under-counts by 111. At a true 70 mph the first turns 578 times a minute, the second 571.
What drivers reported
275/75R24.5 carries 1 complaints. Nobody has filed one naming 265/80R24.5.