215/35R15 vs 225/35R15
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 | 215/35R15 | 225/35R15 | Change |
|---|---|---|---|
| Overall height | 20.9" | 21.2" | +1.3 % |
| Sidewall | 2.96" | 3.10" | +4.7 % |
| Section width | 215 mm | 225 mm | +4.7 % |
| Circumference | 65.7" | 66.6" | +1.3 % |
| Revs per mile | 964 | 951 | -1.3 % |
| Axle height | 10.46" | 10.60" | +3.5 mm |
| Approved rim width | 6–8" | 6–8.5" | overlap 6–8" |
Both are approved on a rim 6" to 8" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 215/35R15. Fit 225/35R15 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 1124 times a minute, the second 1110.