225/35R17 vs 235/35R17
Going from one to the other changes the overall height by +1.2 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/35R17 | 235/35R17 | Change |
|---|---|---|---|
| Overall height | 23.2" | 23.5" | +1.2 % |
| Sidewall | 3.10" | 3.24" | +4.4 % |
| Section width | 225 mm | 235 mm | +4.4 % |
| Circumference | 72.9" | 73.8" | +1.2 % |
| Revs per mile | 869 | 859 | -1.2 % |
| Axle height | 11.60" | 11.74" | +3.5 mm |
| Approved rim width | 6–8.5" | 6.5–8.5" | overlap 6.5–8.5" |
Both are approved on a rim 6.5" to 8.5" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 225/35R17. Fit 235/35R17 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.4 mph | +0.4 |
| 50 mph | 50.6 mph | +0.6 |
| 70 mph | 70.8 mph | +0.8 |
| 90 mph | 91.1 mph | +1.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,119 on the road, so it under-counts by 119. At a true 70 mph the first turns 1014 times a minute, the second 1002.