I have a Brompton-Ortlieb 'O' bag they used 2 small outer pockets, on the back, i replaced one with one of their flat pack water bottle cages..
you have room, mount several and don't put more weight in any one of them than you feel comfortable doing..
mount the U lock with a separate set of velcro straps Or maybe an Abus Bordo Granit 6500, folding link lock in it's pouch?
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Last edited by fietsbob; 05-30-20 at 01:52 PM.