Ok, how well does it work?
I've been trying for months now to find something large enough to fit outside the older 9C 2807's diameter far enough to still allow calipers to clamp around it, but hadn't found anything yet. Been trying various motorcycle shops and people who have them, etc., with no luck yet (usually getting laughed at, called a moron, or just plain ignored).
I thought about cutting a circle out of a stainless steel tabletop I have, but it's too valuable to me as a tabletop, unless I simply can't find anything else.
I looked at all sorts of other things I could repurpose, but had somehow not thought of saw blades.
I'm pretty sure I can find one of those used, in sufficient diameter, so if it actually works well with bicycle disc calipers, I'd be happy enough with that. Can't be too hard to cut the right inner circle diameter out of, and drill the bolt holes.