215/85R17 vs 235/80R17
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 | 215/85R17 | 235/80R17 | Change |
|---|---|---|---|
| Overall height | 31.4" | 31.8" | +1.3 % |
| Sidewall | 7.19" | 7.40" | +2.9 % |
| Section width | 215 mm | 235 mm | +9.3 % |
| Circumference | 98.6" | 99.9" | +1.3 % |
| Revs per mile | 643 | 634 | -1.3 % |
| Axle height | 15.69" | 15.90" | +5.3 mm |
| Approved rim width | 6–8" | 6.5–8.5" | overlap 6.5–8" |
Both are approved on a rim 6.5" to 8" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/85R17. Fit 235/80R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.7 mph | +0.7 |
| 70 mph | 70.9 mph | +0.9 |
| 90 mph | 91.2 mph | +1.2 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,132 on the road, so it under-counts by 132. At a true 70 mph the first turns 750 times a minute, the second 740.
What drivers reported
Nobody has filed a complaint naming 215/85R17. 235/80R17 carries 17.