I've changed slightly the times and now it looks softer. Thank you!
Just one thing about the animation, it pauses stiffly at the ends. I know they slow down at the sides, but not quite so suddenly, so it might be a good idea to add a tiny bit of variance between the two "stopped at sides" frames. You've got a nice illusion of rotation when it's moving, though!
Might be my browser but i think it's a little fast.