im pretty sure l know the guy whos selling this, but ask him for more pictures and what ends up happening is he has a picture of a new bike for a really good price and then when you ask for pictures then the actual photos come and it will be a older version of the bike.
If its shifting side to side it could be that your hub body is loose or has come off, this has happened to me or like other people say it could be that there needs to be a washer in between the cassette and hub.
