DUB, and why SRAM made another standard
SRAM introduced DUB to solve a real problem. Crank spindles had fragmented into 24mm, 30mm and various in-betweens, each needing its own bearings, and no single spindle fitted every frame standard.
DUB settled on 28.99mm — deliberately between 24mm and 30mm. It is large enough to be stiff, and small enough that the bearings still fit inside the narrower frame shells. One spindle, many shells.
The practical consequence for you is simple: a DUB crank needs a DUB bottom bracket, and no amount of adaptation makes a GXP one work in its place.
GXP is the older standard
GXP spindles step from 24mm on the drive side to 22mm on the non-drive side, and the bottom bracket is machined to suit. Plenty of good bikes still run it. It is not obsolete, it is just not DUB.
Which shell do you have?
Threaded shells have visible threads cut into the frame and take the 68/73mm DUB threaded unit. PressFit shells are smooth-bored, and take either the 89.5/92mm MTB unit or the PF30 road one depending on diameter.
Measuring this yourself with the cranks still in the bike is difficult. We do it in a minute with the right tool.
Fit it properly, or it will creak
Pressfit bearings need a press and correct alignment. Forced in with a mallet they sit crooked, wear fast and creak under load — and the creak is then blamed on everything else on the bike for months.
Book it through our workshop, or bring the bike to us in Scott Estate.
Related: the rest of the SRAM drivetrain range.
