245/55R16 vs 255/55R16
Going from one to the other changes the overall height by +1.6 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 245/55R16 | 255/55R16 | Change |
|---|---|---|---|
| Overall height | 26.6" | 27.0" | +1.6 % |
| Sidewall | 5.31" | 5.52" | +4.1 % |
| Section width | 245 mm | 255 mm | +4.1 % |
| Circumference | 83.6" | 85.0" | +1.6 % |
| Revs per mile | 758 | 746 | -1.6 % |
| Axle height | 13.31" | 13.52" | +5.5 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 245/55R16. Fit 255/55R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.5 mph | +0.5 |
| 50 mph | 50.8 mph | +0.8 |
| 70 mph | 71.1 mph | +1.1 |
| 90 mph | 91.5 mph | +1.5 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,163 on the road, so it under-counts by 163. At a true 70 mph the first turns 884 times a minute, the second 870.
What drivers reported
Nobody has filed a complaint naming 245/55R16. 255/55R16 carries 4.