I have been waiting for Shimano to introduce an Ultegra-level compact double “climbing” cassette and derailleur. They finally came out with a matched set. Just this week, my latest wholesale catalog lists the following 10-speed parts:
Ultegra CS-6700 12-30t Cassette
Ultegra RD-6700A 30 tooth (40 wrap) Derailleur
Yahoo. I’m just in the process of building up a new/used Ti bike and plan to put these parts on it.
My current set-up on my carbon bike has a 11-28 cassette with a 50/33 crankset (yes a special French-made 33 and not the usual 34, which I sell on my Distance Biker site). Shimano has always had the 12-30 Tiagra cassette, but it is heavy as it made from steel instead of alloy as with the Ultegra-level cassettes. And, using the old Ultegra or 105 derailleur this cassette was problematic as the cage wasn’t quit long enough.