Great value Deore 2-piece design chainset for 10-speed Dyna-Sys MTB HG-X transmissions. The 2-piece design chainset features an external bottom bracket system which is a lightweight rigid design that is incredibly strong & durable. Lightweight & rigid steel bottom bracket axle. SG-X chainring with patented spike pins give smooth & fast gear shifts under load. Lightweight aluminium outer with steel/glass fibre composite middle & steel inner chainrings. 104 / 64 mm bolt circle diameter. 10-speed Dyna-Sys compatible. 68/73mm BB Shell.