Originally Posted by
Kacee
It is indeed meaningless, because the answer does not affect the recommended course of action. OP should not check his bag if there is a tight connection at EWR. Ergo, he will have his bag in hand when he boards the flight to SJU. Either it will fit overhead or it will not. If it does not fit, it will be gate checked. Either result - bag in overhead bin or bag checked at the gate - is preferable to having it miss the connection at EWR and thus end up in baggage limbo.
Well, those are not the only options.
If the OP can ascertain that the overheads on the specific plane he/she will fly are indeed on the shallower side, he/she could pick a different, more compact carry-on that is more likely to fit and thus the potential of checked bag not making the connection vastly reduced.
Of course, it might be tough to get reliable info on the specific plane being operated and its type of interior configuration, but that hardly means the question is meaningless.