Shimano dura ace r9100 cassetteshimano have retained the traditional close cassette ratios from previous editions of dura ace but with the new r9100 groupset they have also introduced a wide range 11 30t cassette all cassettes in the range will be compatible with the one rear derailleur so you can easily swap your cassettes out based on terrain the cassette is manufactured from a lightweight alloy and carbon fibre spider that houses 6 alloy sprockets and 5 titanium sprockets the largest sproc