235/65R17 vs 215/75R17
Going from one to the other changes the overall height by +2.3 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 235/65R17 | 215/75R17 | Change |
|---|---|---|---|
| Overall height | 29.0" | 29.7" | +2.3 % |
| Sidewall | 6.01" | 6.35" | +5.6 % |
| Section width | 235 mm | 215 mm | -8.5 % |
| Circumference | 91.2" | 93.3" | +2.3 % |
| Revs per mile | 695 | 679 | -2.3 % |
| Axle height | 14.51" | 14.85" | +8.5 mm |
| Approved rim width | 6.5–8.5" | 6–8" | 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 235/65R17. Fit 215/75R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.7 mph | +0.7 |
| 50 mph | 51.2 mph | +1.2 |
| 70 mph | 71.6 mph | +1.6 |
| 90 mph | 92.1 mph | +2.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,231 on the road, so it under-counts by 231. At a true 70 mph the first turns 811 times a minute, the second 792.
What drivers reported
235/65R17 carries 105 complaints. Nobody has filed one naming 215/75R17.