225/35R20 vs 215/35R20
Going from one to the other changes the overall height by -1.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/35R20 | 215/35R20 | Change |
|---|---|---|---|
| Overall height | 26.2" | 25.9" | -1.1 % |
| Sidewall | 3.10" | 2.96" | -4.4 % |
| Section width | 225 mm | 215 mm | -4.4 % |
| Circumference | 82.3" | 81.4" | -1.1 % |
| Revs per mile | 770 | 778 | +1.1 % |
| Axle height | 13.10" | 12.96" | -3.5 mm |
| Approved rim width | 6–8.5" | 6–8" | overlap 6–8" |
Both are approved on a rim 6" to 8" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 225/35R20. Fit 215/35R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.5 mph | -0.5 |
| 70 mph | 69.3 mph | -0.7 |
| 90 mph | 89.1 mph | -0.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,895 on the road, so it over-counts by 105. At a true 70 mph the first turns 898 times a minute, the second 908.
What drivers reported
225/35R20 carries 2 complaints. Nobody has filed one naming 215/35R20.