Why did Lord Krishna have a sudarshana chakra while Lord Rama didn't?

Why did Lord Krishna have a sudarshana chakra while Lord Rama didn't? According to the legends, Ravana got a boon from Lord Shiva that he would not be vanquished by any god. His hubris was such that he didn’t forsee a threat from another man. Thus, the Rama avatar of Vishnu was made as a human and with no access to the divine weapons of gods. Another way to look at this is that Rama was supposed to be the example that humanity should look up to and follow. His struggles were completely human and so were his responses. And that is why he among all the avatars has a whole epic dedicated to him