Joined: Jan 2010
Posts: 9,782
Likes: 1,751
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
I don't think that is the first version of their Chorus 9s rear derailer. Note the absence of a top-knuckle B-tension screw. This one should thus feature the later pull ratio common with 10s mechs, and the pulleys may even have "9/10 speed" molded into the plastic.