225/65R20 vs 235/60R20
Going from one to the other changes the overall height by -1.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/65R20 | 235/60R20 | Change |
|---|---|---|---|
| Overall height | 31.5" | 31.1" | -1.3 % |
| Sidewall | 5.76" | 5.55" | -3.6 % |
| Section width | 225 mm | 235 mm | +4.4 % |
| Circumference | 99.0" | 97.7" | -1.3 % |
| Revs per mile | 640 | 648 | +1.3 % |
| Axle height | 15.76" | 15.55" | -5.3 mm |
| Approved rim width | 6–8.5" | 6.5–8.5" | overlap 6.5–8.5" |
Both are approved on a rim 6.5" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 225/65R20. Fit 235/60R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.6 mph | -0.4 |
| 50 mph | 49.3 mph | -0.7 |
| 70 mph | 69.1 mph | -0.9 |
| 90 mph | 88.8 mph | -1.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,869 on the road, so it over-counts by 131. At a true 70 mph the first turns 747 times a minute, the second 757.
What drivers reported
Nobody has filed a complaint naming 225/65R20. 235/60R20 carries 1.