Dura-Ace cranksets are regarded as near perfection when it comes to stiffness and chainring shifting performance. Shimano continues its use of hollow forged aluminum crank arms, which have been further optimized for the brand new 9100 series group. Now featuring a black finish, the Shimano Dura-Ace 9100 Crankset features a 4-bolt design that allows compact, mid-compact, and standard chainrings to fit on the same crank arm set. To maximize frame compatibility, Shimano uses a 24mm bottom bracket spindle, dubbed Hollowtech II. This spindle standard works on nearly every frame, including standard threaded, Shimano’s own BB86, and BB30 and PF30 bottom brackets, with the use of adaptors. The next differentiator is Shimano’s chainring design. Compared to nearly every other chainring on the market, Dura-Ace rings are next-level. Utilizing a sandwich-style composite structure, the rings are extremely stiff, allowing the chain to quickly shift gears. The profile of the teeth are also revised, to further enhance shift performance. We’re offering the Shimano Dura-Ace 9100 Crankset in its three most common lengths (170mm, 172.5mm, and 175mm) and its three most popular chainring sizes (50/34, 52/36, and 53/39). For additional sizes, please call or email us at firstname.lastname@example.org.