265/35R20 vs 245/35R20
Going from one to the other changes the overall height by -2.0 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/35R20 | 245/35R20 | Change |
|---|---|---|---|
| Overall height | 27.3" | 26.8" | -2.0 % |
| Sidewall | 3.65" | 3.38" | -7.5 % |
| Section width | 265 mm | 245 mm | -7.5 % |
| Circumference | 85.8" | 84.0" | -2.0 % |
| Revs per mile | 739 | 754 | +2.0 % |
| Axle height | 13.65" | 13.38" | -7.0 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 265/35R20. Fit 245/35R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 49.0 mph | -1.0 |
| 70 mph | 68.6 mph | -1.4 |
| 90 mph | 88.2 mph | -1.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,798 on the road, so it over-counts by 202. At a true 70 mph the first turns 862 times a minute, the second 880.
What drivers reported
Nobody has filed a complaint naming 265/35R20. 245/35R20 carries 6.