Dura ace moves to the next generation tested in competition and taken to victory by pro riders in all conditions including the 2012 tour de france team sky cutting edge technology for the ultimate in control and confidence rider tuned means dura ace works the way you want it the new 11 speed cassettes are available in a range of sizes including a wide range 11 28 option one cassette to use all year round smooth fast shifting guaranteed key features hyperglide sprockets have a com