245/50R16 vs 235/55R16
Going from one to the other changes the overall height by +2.1 %. That is inside the 3% band, so it fits and the speedometer stays close.
Side by side
| Measure | 245/50R16 | 235/55R16 | Change |
|---|---|---|---|
| Overall height | 25.6" | 26.2" | +2.1 % |
| Sidewall | 4.82" | 5.09" | +5.5 % |
| Section width | 245 mm | 235 mm | -4.1 % |
| Circumference | 80.6" | 82.2" | +2.1 % |
| Revs per mile | 786 | 770 | -2.1 % |
| Axle height | 12.82" | 13.09" | +6.8 mm |
| Approved rim width | 7–9" | 6.5–8.5" | 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 245/50R16. Fit 235/55R16 and the needle stops telling the truth.
| Needle says | You are doing | Out by |
|---|---|---|
| 30 mph | 30.6 mph | +0.6 |
| 50 mph | 51.0 mph | +1.0 |
| 70 mph | 71.5 mph | +1.5 |
| 90 mph | 91.9 mph | +1.9 |
The odometer drifts with it. Ten thousand miles on the dial are really 10,207 on the road, so it under-counts by 207. At a true 70 mph the first turns 917 times a minute, the second 899.