Custom Frame Bag recommendations

Thanks!

Waterproofness is a tricky subject, the only truly waterproof bags are welded rather than sewn, like Ortlieb. But my frame bags have been tested in proper Dutch rain and managed to keep the contents dry.

I use fully waterproof outer and liner fabric, leaving two points of entry for water: the seams and the zippers, with the zippers being the weak spot. I use YKK aquaguars water resistant zips, a more waterproof alternative would be a regular zip with a flap over it like the pictured Gramm bag.

The closest you’ll get to waterproof is a roll top frame bag, but they’re a bit of a faff to open and add some bulk so they’re not great if your pedaling style has your knees close the top tube.