SRAM’s new DUB thru-axle design necessitates a new bottom bracket. The 28.99mm spindle fits in all current bottom bracket shells. All you need to do is get the bottom bracket that matches your frame’s bottom bracket standard. DUB is an acronym for Durable Unified Bottom bracket. It should fit in just about every mountain bike on the market today and they anticipate it will fit just about everything that will come to market tomorrow. It’s durable both because the greater diameter spindle increases stiffness and the larger bearings rolling against it run more easily. Unified because this one crank can be used on all frames. SRAM has DUB options for the old-school English-threaded (BSA) bottom bracket, the newer BB30 and PF30 standard and the mountain bike only BB92. You just need to select the one that matches the standard you need it to fit. The DUB BSA bottom bracket weighs 76g, the BB30 82g, PF30 89g, and 71g for BB92. The BSA option comes with spacers to you can have 679, 73, 73 Guide, or 100mm shells. The BB92 option comes with spacers so you can adapt to 89.5, 92, or 121mm (Fat Bike) shells. The BB/PF30 option has a spacer on the right side. The SRAM DUB Bottom Bracket makes crank installation easy and the central movement smooth and long lasting.