205/70R20 vs 215/70R20
Going from one to the other changes the overall height by +1.8 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 205/70R20 | 215/70R20 | Change |
|---|---|---|---|
| Overall height | 31.3" | 31.9" | +1.8 % |
| Sidewall | 5.65" | 5.93" | +4.9 % |
| Section width | 205 mm | 215 mm | +4.9 % |
| Circumference | 98.3" | 100.1" | +1.8 % |
| Revs per mile | 644 | 633 | -1.8 % |
| Axle height | 15.65" | 15.93" | +7.0 mm |
| Approved rim width | 5.5–7.5" | 6–8" | overlap 6–7.5" |
Both are approved on a rim 6" to 7.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 205/70R20. Fit 215/70R20 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.9 mph | +0.9 |
| 70 mph | 71.2 mph | +1.2 |
| 90 mph | 91.6 mph | +1.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,176 on the road, so it under-counts by 176. At a true 70 mph the first turns 752 times a minute, the second 739.
What drivers reported
205/70R20 carries 2 complaints. Nobody has filed one naming 215/70R20.