Originally Posted by
alan s
Rather than the rack going straight to the dropout, the rack is designed to clear a caliper mounted on the back of the seatstay. Kind of an L-shaped mount, rather than straight. This pushes the rack stays outboard, without which you would have to come up with a DIY installation.
Yup. Think of it as a regular rack, but where it mounts to the stay there's about 3/4 inch or so standoff to clear the caliper. You could easily use a regular rack spread with a stack of washers on each side, but the disc specific ones just look neater. I have one of the same racks alan s does.