245/60R16 vs 255/55R16
Going from one to the other changes the overall height by -1.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 245/60R16 | 255/55R16 | Change |
|---|---|---|---|
| Overall height | 27.6" | 27.0" | -1.9 % |
| Sidewall | 5.79" | 5.52" | -4.6 % |
| Section width | 245 mm | 255 mm | +4.1 % |
| Circumference | 86.6" | 85.0" | -1.9 % |
| Revs per mile | 731 | 746 | +1.9 % |
| Axle height | 13.79" | 13.52" | -6.8 mm |
| Approved rim width | 7–9" | 7–9.5" | overlap 7–9" |
Both are approved on a rim 7" to 9" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 245/60R16. Fit 255/55R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 29.4 mph | -0.6 |
| 50 mph | 49.0 mph | -1.0 |
| 70 mph | 68.7 mph | -1.3 |
| 90 mph | 88.3 mph | -1.7 |
The odometer drifts with it. Ten thousand miles on the dial are really 9,807 on the road, so it over-counts by 193. At a true 70 mph the first turns 853 times a minute, the second 870.
What drivers reported
Nobody has filed a complaint naming 245/60R16. 255/55R16 carries 4.