245/80R17 vs 265/70R17
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 | 245/80R17 | 265/70R17 | Change |
|---|---|---|---|
| Overall height | 32.4" | 31.6" | -2.5 % |
| Sidewall | 7.72" | 7.30" | -5.4 % |
| Section width | 245 mm | 265 mm | +8.2 % |
| Circumference | 101.9" | 99.3" | -2.5 % |
| Revs per mile | 622 | 638 | +2.5 % |
| Axle height | 16.22" | 15.80" | -10.5 mm |
| Approved rim width | 7–9" | 7.5–9.5" | 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 245/80R17. Fit 265/70R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.2 mph | -0.8 |
| 50 mph | 48.7 mph | -1.3 |
| 70 mph | 68.2 mph | -1.8 |
| 90 mph | 87.7 mph | -2.3 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,745 on the road, so it over-counts by 255. At a true 70 mph the first turns 725 times a minute, the second 744.
What drivers reported
Nobody has filed a complaint naming 245/80R17. 265/70R17 carries 174.