I was looking around for some ideas for soft bag supports for my cyclerack, and while I very much like the cycleracks add-on mounts, they're not exactly what I was looking for, and .. well, I'm saving my $60 at the moment for some new pegs
Part of what irritates me about all the mounting setups I've seen is that they're heavy.. or at least they look it, I don't own any to feel for myself. They all seem to be made out of steel tubing, though, which I like for its sturdiness, but I really don't want the extra weight. The cyclerack adds plenty. I've got some old foreign military surplus over-the-shoulder type bags with a water-resistant flap type cover, and really cool old leather strapping, and wanted to put them to use as saddle bags on the TW. The backs are unprotected from water, so, I don't know how they'll fair, but there really is only one way to find out.
I opted to use some 1/8" aluminum flatstock from the local hardware store to build my supports: 6 pieces in all, and a requirement was that I be able to bolt it together, because I'm not setup to weld aluminum. What I do like about it, though, is that its extra easy to work with otherwise, and tends to be tough enough for my uses. What I don't like about it: same thing as steel, I haven't figured out how to properly bend it into a U-shape without taking a lot of time laying it out. So, I tend to have extra material hanging off where I build my 'clamps' on the ends.
The build is fairly simple, requiring a handful of 1/4" grade 5 or better bolts and nuts, a drill bit that'll poke a hole big enough for a 1/4" bolt to go through, and roughly: (2) 4ft 1" wide aluminum bars, and (1) 4ft 3/4" wide aluminum bar. I cut the 1" wide bars into two ~equal lengths each, with about 8-10" of leftover from each 4ft, and bend one end of each piece into a "U" sized for the cyclerack (4 pieces with "U"s total). They get marked, and drilled for a bolt to go through the "U" end to clamp with, and the other end to attach another support. They just hang over the cyclerack. The piece that adds some rigidity uses the license plate bolts, and is made from the 3/4" flat stock: 2 pieces get cut off, equal length, and bent twice, then drilled to match the pattern for the hanging pieces, and the other end drilled to attach to the back of the license plate.
Put altogether, its fairly solid, for randomly bolted together thin aluminum bars, and probably the lightest weight setup I've seen yet. I've still gotta trim off some excess, round some corners, and maybe re-engineer the straps on the bags, but so far I'm liking it. Doesn't detract too much from the TW's sex appeal, and certainly performs the main goal: keeping the bags in place and away from the muffler and moving parts.