Originally Posted by
Chr0m0ly
The single attachment to the brake bridge racks seem every bit as solid as the double support versions. The weight is taken by the rack stays, the attachment to the bridge just keeps it from from moving forward or backward.
That's not been my experience, with any rack I've mounted. I've found that the most stable are those with integral seat stay rods (e.g. Blackburn SS-1). Racks employing twisted stainless stay braces attached to "cheerio" seat stay braze-ons, or into threaded eyelets in holes in the stays (seen some '90s MTBs/hybrids) are second. Stainless stay braces attached to "p-straps" on the stays, or a single brace going to the brake bridge, allow the rack to move more. This is just personal experience, bike commuting for work for 20+ years, and my wife and I doing 90% of our shopping by bike.
Good sleuthing on
natterberry 's part, BTW. My first clue was the absence of water bottle braze-ons, and that icky band-mounted cage.