Thule 598 users

What is the distance between the 2 mounting points for the cross bars?

Weighing up whether to go with roof rails with cross rails or standard roof bars. My hope is that roof bars are good to go and the mounting points on the roof aren’t craply spaced

Fully adjustable so I’m sure they’d fit any average spaced set of bars.

What’s max length?

You can adjust but within limits, and also be aware that the bike grabbing arm is fixed to where the rack mounts to the (usually forward) roof bar. I.e. if you have a very unusual configuration of roof bars it might limit the size of bike that would fit on the rack.