265/30R20 vs 245/35R20
Going from one to the other changes the overall height by +1.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 265/30R20 | 245/35R20 | Change |
|---|---|---|---|
| Overall height | 26.3" | 26.8" | +1.9 % |
| Sidewall | 3.13" | 3.38" | +7.9 % |
| Section width | 265 mm | 245 mm | -7.5 % |
| Circumference | 82.5" | 84.0" | +1.9 % |
| Revs per mile | 768 | 754 | -1.9 % |
| Axle height | 13.13" | 13.38" | +6.3 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 265/30R20. Fit 245/35R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.3 mph | +1.3 |
| 90 mph | 91.7 mph | +1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,187 on the road, so it under-counts by 187. At a true 70 mph the first turns 896 times a minute, the second 880.
What drivers reported
Nobody has filed a complaint naming 265/30R20. 245/35R20 carries 6.