I think the SQR holds the bag much more rigidly. There is very little sway as the bags have a metal frame that hooks into the SQR at a couple of points
Nice one. This is looking like it could be the solution.
Just need to decide between the SQ Slim and Tour now. As I don't use a laptop or carry files I reckon the Tour is the way to go. Side pockets for a race cape and tools sounds ideal.
Do you reckon it's a better option to the SQR? It's certainly lighter.