265/65R22 vs 245/75R22
Going from one to the other changes the overall height by +2.5 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/65R22 | 245/75R22 | Change |
|---|---|---|---|
| Overall height | 35.6" | 36.5" | +2.5 % |
| Sidewall | 6.78" | 7.23" | +6.7 % |
| Section width | 265 mm | 245 mm | -7.5 % |
| Circumference | 111.7" | 114.6" | +2.5 % |
| Revs per mile | 567 | 553 | -2.5 % |
| Axle height | 17.78" | 18.23" | +11.5 mm |
| Approved rim width | 7.5–9.5" | 7–9" | overlap 7.5–9" |
Both are approved on a rim 7.5" to 9" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 265/65R22. Fit 245/75R22 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.8 mph | +0.8 |
| 50 mph | 51.3 mph | +1.3 |
| 70 mph | 71.8 mph | +1.8 |
| 90 mph | 92.3 mph | +2.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,255 on the road, so it under-counts by 255. At a true 70 mph the first turns 662 times a minute, the second 645.