215/85R17 vs 235/75R17
Going from one to the other changes the overall height by -1.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/85R17 | 235/75R17 | Change |
|---|---|---|---|
| Overall height | 31.4" | 30.9" | -1.6 % |
| Sidewall | 7.19" | 6.94" | -3.6 % |
| Section width | 215 mm | 235 mm | +9.3 % |
| Circumference | 98.6" | 97.0" | -1.6 % |
| Revs per mile | 643 | 653 | +1.6 % |
| Axle height | 15.69" | 15.44" | -6.5 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 235/75R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.5 mph | -0.5 |
| 50 mph | 49.2 mph | -0.8 |
| 70 mph | 68.9 mph | -1.1 |
| 90 mph | 88.5 mph | -1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,837 on the road, so it over-counts by 163. At a true 70 mph the first turns 750 times a minute, the second 762.
What drivers reported
Nobody has filed a complaint naming 215/85R17. 235/75R17 carries 8.