SRAM’s new ‘forward thinking, backward compatible’ BB and crankset standard

Before you shake your head and scream at the sky at the prospect of another BB standard, SRAM DUB will fit anywhere existing GXP and BB30 cranks go.

DUB will fit your frame.

SRAM Dub need to know

  • One axle diameter to take over from GXP and BB30
  • Compatible with all existing BB sizes and frames
  • Designed to provide proper bearing sealing for all BB styles
  • 28.99mm axle diameter is stiffer than GXP yet lighter than BB30
  • DUB has allowed SRAM to create its lightest cranksets ever
  • No new tools are needed

The new Durable Unifying Bottom Bracket, or DUB for short sees SRAM radically changing their entire crankset and bottom bracket approach for 2018.

DUB shrinks the diameter of the axle just enough to allow for proper sealing with all bottom bracket configurations. A casual glance will find the new DUB axle size barely discernable from BB30. Closer measurements show it actually has a diameter of 28.99mm. That 1.01mm makes all the difference.

D(urable) U(nifying) B(ottom Bracket)


The story behind DUB is actually a pretty simple one. Faced with the desire to create the lightest, stiffest cranksets and providing better sealing for its BBs, SRAM realised that sticking to current GXP and BB30 axle standards pretty much restricted them from making any more significant developments. Everything looked to be leading up to a compromise between the better sealing found on GXP’s BSA (threaded) BBs and the stiffest, lightest performing BB30, 30mm diameter oversized axle cranks. And so DUB was born.


Any BB size for any frame.

Better sealing

SRAM was able to work directly with bearing manufacturers to create a range of bottom brackets that should hopefully last longer than current BB30/PF30 designs. The new bottom brackets have tighter tolerances, improved bearing profiles and additional o-ring seals. Add to this a change to the assembly process at SRAM’s facilities.


Even in the least durable shell sizes like PF30, the new DUB versions have outperformed their old versions significantly.

>>> How to replace a press fit BB

SRAM’s lightest cranks yet

The other goal of DUB was to build SRAM’s lightest crankset to date. By reducing the axle diameter, employing some new machining techniques (including a lighter Eagle X-Sync 2 SL chainring) and some carbon magic has allowed the new XX1 Eagle DUB SL chainset to tip the scales at a miniscule 490 grams. Including bottom bracket. That’s lighter even than Race Face’s NEXT SL.


That’s 490g including BB! And these are our photos so we saw it with our own eyes.

Super clean internal construction.

SRAM will be providing the following cranks in DUB format:

  • XX1 Eagle DUB SL, £510-£520, available from March
  • XO1 Eagle DUB, £480-£490, available from February
  • GX Eagle DUB, £135-£185, available from February
  • Descendent Carbon DUB, £255, available from February
  • Descendent 6K DUB, £105, available from May
  • Stylo Carbon DUB, £255-£305, available from February
  • Stylo 6K DUB, £105, available from May

£105 for the new Descendent alloy crankset

DUB bottom brackets will be priced £32-£44. Availability will also be from February.