Originally Posted by rousseau

Just started in the last day or two. It happens when I move the bike side to side, either in the saddle or out of it, pedalling or not. It's even creaking when I'm standing still. The bolts at both ends of the stem and seatpost are good. I'm fairly confident this isn't an issue with the saddle or handlebar. Any ideas?

Stationary: https://www.youtube.com/watch?v=gSBixdYq0zk
While riding: https://www.youtube.com/watch?v=WXNLefYrdEQ