Hi,
Now a days most of airline allowd MAX 158cm baggage while traving to USA but I have 159cm size bag (as specified by bag manual).
Will they allowed my bag as free check-in ?
It will be their discretion. Usually they are not very strict about it unless it doesn’t go into the overhead bin. At times, they also ask you to but the bag inside the basket kept at the airport to ensure it goes into the overhead bin.