165/50R16 vs 165/55R16
Going from one to the other changes the overall height by +2.9 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 165/50R16 | 165/55R16 | Change |
|---|---|---|---|
| Overall height | 22.5" | 23.1" | +2.9 % |
| Sidewall | 3.25" | 3.57" | +10.0 % |
| Section width | 165 mm | 165 mm | 0.0 % |
| Circumference | 70.7" | 72.7" | +2.9 % |
| Revs per mile | 897 | 871 | -2.9 % |
| Axle height | 11.25" | 11.57" | +8.3 mm |
| Approved rim width | 4.5–6" | 4.5–6" | overlap 4.5–6" |
Both are approved on a rim 4.5" to 6" wide. If yours is in that band, this is a tire change and nothing else.
What the speedometer will say
Calibrated for 165/50R16. Fit 165/55R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.9 mph | +0.9 |
| 50 mph | 51.4 mph | +1.4 |
| 70 mph | 72.0 mph | +2.0 |
| 90 mph | 92.6 mph | +2.6 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,289 on the road, so it under-counts by 289. At a true 70 mph the first turns 1046 times a minute, the second 1017.