Shimano Dura Ace Rear Derailleur 12s RD-R9250rdShimano Dura Ace Di2 RD R9250 Rear Derailleur 12 speed Dura Ace R9200 Never Compromise The Science of Speed. Speed was the mainspring in the development of this 12 speed road bike series of a new generation. Several years of research produced those innovations that make the Shimano Dura Ace R9200 even faster. Every component has been revised, refined and optimised to enable the decisive seconds of advantage whether as a breakaway from the peloton or