215/80R15 vs 225/75R15
Going from one to the other changes the overall height by -0.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 215/80R15 | 225/75R15 | Change |
|---|---|---|---|
| Overall height | 28.5" | 28.3" | -0.9 % |
| Sidewall | 6.77" | 6.64" | -1.9 % |
| Section width | 215 mm | 225 mm | +4.7 % |
| Circumference | 89.7" | 88.9" | -0.9 % |
| Revs per mile | 707 | 713 | +0.9 % |
| Axle height | 14.27" | 14.14" | -3.3 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 215/80R15. Fit 225/75R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.7 mph | -0.3 |
| 50 mph | 49.6 mph | -0.4 |
| 70 mph | 69.4 mph | -0.6 |
| 90 mph | 89.2 mph | -0.8 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,910 on the road, so it over-counts by 90. At a true 70 mph the first turns 824 times a minute, the second 832.
What drivers reported
Nobody has filed a complaint naming 215/80R15. 225/75R15 carries 258.