225/60R15 vs 245/55R15
Going from one to the other changes the overall height by -0.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 225/60R15 | 245/55R15 | Change |
|---|---|---|---|
| Overall height | 25.6" | 25.6" | -0.1 % |
| Sidewall | 5.31" | 5.31" | -0.2 % |
| Section width | 225 mm | 245 mm | +8.9 % |
| Circumference | 80.5" | 80.5" | -0.1 % |
| Revs per mile | 787 | 788 | +0.1 % |
| Axle height | 12.81" | 12.81" | -0.3 mm |
| Approved rim width | 6–8.5" | 7–9" | overlap 7–8.5" |
Both are approved on a rim 7" 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 225/60R15. Fit 245/55R15 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.0 mph | -0.0 |
| 50 mph | 50.0 mph | -0.0 |
| 70 mph | 69.9 mph | -0.1 |
| 90 mph | 89.9 mph | -0.1 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,992 on the road, so it over-counts by 8. At a true 70 mph the first turns 918 times a minute, the second 919.
What drivers reported
225/60R15 carries 9 complaints. Nobody has filed one naming 245/55R15.