The all-new SRAM DUB crankset and bottom bracket collection introduces the final piece of their “systems engineering” puzzle, giving them a completely optimized drivetrain. The idea was to take the respective benefits of BB30 and GXP, combine them, then eliminate any of the drawbacks of either system. The result is a more standardized design that lets them drop weight, improve performance, simplify installation regardless of what frame you have.

While they’ve been quite innovative with their drivetrain parts over the years, introducing the XD freehub body interface, 12-speed, 1x drivetrains, etc… SRAM’s cranks have stayed largely the same. No longer. They’re (rightfully) hesitant to call this a new standard. Technically, it’s a new spindle & BB design that will be backwards compatible with all existing bottom bracket shells.

sram dub universal mountain bike crankset fits any bottom bracket standardAt the cranks, DUB combines the durability and simplicity of a steel 24-to-22mm GXP spindle and bottom bracket combo, but the lighter weight and improved stiffness of the oversized alloy 30mm spindle found on BB30. And they’re doing all that with a single crankset spindle size (which happens to be 28.99mm in diameter), so all cranks are the same regardless of what type of bike they’re going on. The benefit of all this is that they can optimize the cranks’ layup or forging as best as possible because they only have to design one single crankset at each level.

what is the sram dub standard

For the bottom bracket, they took the four most common designs and created a DUB bottom bracket that puts the bearings outside the frame in most cases. This not only gives them a wider stance (which improves stiffness), but combined with the slightly narrow spindle, it also lets them use larger bearings (for better durability). It also created room for proper seals. Basically, the bearings and BB shells or cups no longer have to compromise to fit the frame.

In a nutshell, DUB means one single crank design that fits every BB standard out there, with a BB that fits that spindle into any frame standard. Except they’ll also have fat bike spindle widths and Q-factor options. So, technically, they’re not exactly inventing a new standard, but what they’re calling a “standard killer” because it works with everything. SRAM’s been working on this project for at least three years, coordinating their teams in Germany, San Luis Obispo and Chicago. For now, it’s launching on XX1, X01 and GX Eagle, Descendant carbon and alloy, and Stylo carbon and alloy. For these products DUB immediately replaces the original GXP and BB30 options.

WEIGHT SAVINGS & TECH DETAILS

2018 SRAM XX1 DUB and X01 DUB cranksets

DUB introduces a complete, “system engineered” drivetrain for SRAM, and they say it’s now the lightest in class now, even beating Race Face Next SL by ~20 grams.

Weight savings come from using an oversized alloy spindle (as opposed to the steel GXP spindles), which is bonded to the crank arm rather than pressed on like their current designs. Layup on the carbon crank arms is very similar, though they do get a bit stronger and stiffer, with the XX1 getting further refinements to save additional grams.

XX1 Eagle DUB cranks with BSA bottom bracket & 34t chainring comes in at 497g. Photo courtesy DR.

The XX1 Eagle cranks’ claimed weight is 422g with 32-tooth X-Sync2 chainring and 175mm arms. Retail is $515 – $525 (€570 – €585 / £510 – £520), available in March 2018.

The X01 cranks are a bit tougher, aimed at Trail/Enduro riders and come in at a claimed 471g (32t, 175mm). Retail for $485 – $495 (€540 – €550 / £480 – £490), available in February.

2018 SRAM GX Eagle and Descendant carbon alloy DUB cranksets

GX Eagle comes in at $135 – $185 (€150 – €205 / £135 – £185, available February) with a claimed weight of 621g with 7000-series forged alloy arms. All three Eagle groups (XX1, X01 and GX) come in three spindle widths: Boost and Fat Bike spindles (with chainring configurations for 4″ and 5″ tires). All cranks shown here are offered in 170mm and 175mm, and the GX Eagle adds a 165mm option.

The Descendant Carbon hits the scales at 555g (32t, 175mm) with the cold-forged X-Sync2 chainring. Retail is $260 (€290 / £255), available February. The alloy Descendant 6K gets their steel chainring and a weight of 717g ($105 / €115 / £105), available in May.

2018 Stylo DUB carbon and alloy cranksets with universal fit BB standard

The Stylo cranks got a refresh in the summer of 2017, and the new DUB cranksets carry those changes over for the new spindle design. They come in carbon (555g; $260-$310 / €290-€345 / £255-£305; available in Boost and Fat 4/5; February 2018) and 6000-series alloy (705g; $105 / €115 / £105; Boost only; May 2018).

SRAM DUB BOTTOM BRACKETS

2018 SRAM DUB bottom bracket options for PFBB30 BSA threaded and more

Between these four DUB bottom brackets, SRAM says you can fit their new cranks into any modern frame. Clockwise from top left are:

  • BB30 (aka MTB73 / 82g / alloy cups)
  • PFBB30 (aka PF30, MTB73 / 68-92mm / 89g / alloy cups)
  • BSA threaded (English BSA, MTB73, MTB68SP, MTB73E, MTB100 / 73-100mm / 76g / alloy cups)
  • PFBB (aka MTB89.5, MTB92, MTB121 / 89-121mm / 71g / steel cups)

Retail ranges from $38 – $50 (€38-€52 / £32-£44), available starting February through May depending on model.

SRAM.com

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80 COMMENTS

  1. Point of clarification: are 30mm spindles actually 28.99mm, or did SRAM decide that something 1.01mm skinnier than an existing standard was a good idea?

    • BB30 refers to the spindle diameter, so yes the DUB spindle is indeed 1.01 mm smaller in diameter. I’m guessing that somehow they determined it to be the best compromise to fit the greatest number of MTB bottom bracket designs. My guess is that it allows PFBB use without premature bearing wear.

        • Dude, let’s think this “new standard” through. One crank can move from bike to bike with the potential new purchase of a BB (which get replaced often anyways and are about the cheapest part on a bike). This will help so many people in so many ways. And besides, they say the added space allows them to use bigger stronger bearings and better seals. Also, BB30 was designed by Cannondale, and BSA was popularized by Shimano. Chill.

          • BSA isn’t Shimano, it stands for British Standard Cycle. 😉

            JIS is the square taper standard popularized by Shimano as is Octolink.

            • BSA actually stands for Birmingham Small Arms, a now obscure company that exists in name only, but back in the late 1800s they put some of the first hub gears into mass production, as well as designing a bottom bracket standard that’s still the best 130 years later.

            • “JIS” also has nothing to do with shimano. It stands for Japanese Industrial Standards. JIS and ISO tapers exist for square taper BBs, but this has nothing to do with the actual bottom bracket shell design. It only refers to the difference in how the spindle is tapered. Shimano did have a JIS version of square taper, but Octalink is NOT square taper at all and completely unrelated to these standards.

              BSA specifically only refers to the threading pitch and style (being reverse on one side), also known as an “English” and as stated above, its existence predates nearly all current component manufacturers.

  2. Blah blah reduce manufacturing overhead blah. Gotcha. If you want to make more money, you have to find efficiencies somewhere. I see the logic, but it’s the usual spin.

    They’re optimizing for SKUs, no need to get excited, your existing cranks/frame are fine. If you want these they’ll likely come on a new compete anyways.

  3. No need to rush out and buy this new stuff, but I think this is a step in the right direction. Essentially I see this as Sram realizing that the 30mm Axle was a mistake and they should have gone a wee bit smaller in the first place. I think this is a good thing though….light cranks, *hopefully* better bearings……as long as the cranks are durable this is nice.

  4. 30mm axles also fit into any bottom bracket. Since enduro brought out the custom bearings to fit 30mm axles into 41mm press fit shells (double row stainless bearings ) there hasn’t been any problems. I’ve had 2.5 years and still counting, with my 41/30 enduro bottom bracket.

    • Correction: 30mm spindles fit in any BB as long as they’re long enough. BB30 spindles aren’t long enough for BB386 or BB30A at the moment.

  5. Gah! By introducing a new spindle diameter, regardless of the justifications, SRAM have introduced a new standard for shops and consumers to keep track of.

    Maybe 30mm spindles aren’t ideal (though they have gotten pretty good for everything but bb92), but I know that my 30mm race face and rotor cranks and BBs will all play well together and that I have a fighting chance of finding bearings when I need them.

    What dm chairing interface are they using? Have they added a third size there too?

    So close but…

  6. This eliminates the increased heel clearance of true BB30 / PF30 cranks for those of us who need it. A step backward for consumer choice in my opinion.

  7. Honestly, not sure how I feel about this. SRAM basically copied what Rotor has been doing with their crankset line up. Rotor has the BSA30 as an option for quite some time now, and it works perfect for people that wants to run 30mm spindle with BSA BB. THM also has the same option. If larger bearing was needed, BSA30 could easily be redesigned to incorporate larger bearings. SRAM needs to stop with improving existing standards marginally and branded as something else. How about focus on things that actually matters? Ergonomics on their Hydraulic road shifter is poor. The brake bleeding procedure could be simplified. It’s extremely annoying and aggravating. The boost spacing never really made much sense when the 150mm spacing already exist.

    • Exactly, Rotor had this for years. And yes, boost makes no sense if they could have gone 150mm. Good news I think it’s that when you buy a new bike, never comes with Rotor, and Rotor systems are expensive. Of course, Shimano will always be more reliable, but we all know that already.

      • A common mistake in comparing apples with oranges. Boost is essentially 141 hub width plus 3.5mm to fit in the recess machined in both right a left dropouts to locate the axle for easy skewer insertion. It also allows for a 3mm shift in chainline to accommodate plus size tires while retaining the narrow Q factor associated with 67 and 73mm BB shells. 150 moves every thing out 7.5mm each side and requires a wider Q factor and 83mm B.B. shell to work. If made like the 142 (135 actual) or 148 (141 actual) standard, 150mm tear ends measure out to 157mm.

  8. you lost me at bonded spindle. the Race Face system is so much better. if i want to more my $500 cranks from a regular bike to a fat bike or a 197 rear to 177 rear frame i just have to get a different spindle. not a new $500 crankset.

  9. I like the standardization (SKU optimizing as mentioned above) but hasn’t Shimano kind of been doing this for a while now? I’ve had the same 24mm spindle XTs on my threaded BB steel hardtail, BB92 carbon hardtail, and PF30 alu dually. I think the real news is the changes to their BBs but I don’t guess that’s sexy enough. Did they finally kill that stupid GXP BB shim that wears out annually or sooner?

  10. SRAM’s commitment to making the least compatible and least reliable BB on the market is incredible.
    And really the cranks aren’t THAT awesome.
    Anyone remember those terrible e13 cranks with weird bearings and a triangular NDS arm interface?
    You probably don’t b/c they didn’t get along with anything. That design and its “standard” went the way of the dinosaur in a few seasons.
    How is this different?

    • Those E13 cranks are still around and still have the odd toroidal axle end. E13 got them (mostly) right in the end, whatever was wrong with the early ones they figured it out.

    • Their alu cranks are durable but the nextsl arent. Just google it
      My 2 cranksets also failed the same way everyone elses has. The rf bsa bb is also absolute garbage. Again mine failed repeatedly the exact same way everyone say it does. Google that too. Their other bbs are ok thought not great. You can also directly check all the threads on mtbr…

    • agreed but SRAM is forcing OEM’s to spec all SRAM complete drivetrains for Eagle
      YES, FORCING their crap cranks on the masses

  11. “It also created room for proper seal.” I’ll have to let somebody else test this, because I’m not buying anymore of the cranksets until this can be confirmed. I bought a XTR crankset online for the price I spent on Sram bb per year.

  12. I hope this lets them put plastic between the spindle and the bearings, like they’ve been doing on their PF30 bottom bracket bearings for the last couple years. Total noise killer. But on their PF30, they got custom bearings that are actually 43x31mm, to make room for their plastic hat. Now I guess they can use a standard 42×30 bearing and still get the plastic hat. How it should have been all along…

  13. I pity the cannondale road crowd, for bb30A frames like the Synapse and SS Evo’s left out in the cold, but… it’s their own fault really.

  14. This makes sense. 24mm axle cranks are heavy. 30mm are cool but with most BB interface end up with too small bearing. This should work fine. The price looks high but will probably be lower quite fast.

  15. Bless you Shimano for staying above the fray of ever changing crank standards. Let us cheer the dull boredom of exceptional product that fits everything. The standard that Shimano needs to perfect is MAP and not enticing the industry to strangle itself.

  16. Too bad they don’t do T47BB, but probably Chris King will just make a different adapter shim for theirs, which is a far more durable BB anyways. Will they use this on road/CX cranks? Will it have big enough rings for Road/CX? Will there be a double ring/spider for that use, like Easton?

  17. 386EVO is missing too. I guess companies like Wheels Manufacturing will step up. Wheels Mfg already makes T47 for 24 mm, 24/22 mm, and 30 mm cranks.

  18. and i still run a 24mm axle with bsa threaded axle, no problems here.

    if i wait it out then someone will make another threaded standard to fit 30mm, better and optimize it to be better than ever before and while they do it, it will be to fit around a new tyre size that fits somewhere between 650+ and trophy trucks because there awesome offroad 🙂

    • i just saw the shimano fan boys should comment, just to clarify i use raceface 24mm as i managed to snap a saint axle once, not good.

  19. For me, this would be more useful on a road bike. I’ll have my X.9 crankset for the next 10 years probably, no need to upgrade. But I would definitely upgrade my road bike to Red or Force DUB if it existed.

  20. This is all about IP licensing. SRAM is looking to capitalize on their product and not have to pay Spec for the 30mm spindle. Congrats SRAM, screw the customer
    so you can get around IP….

  21. This is Boost all over again…give it time everyone will retool and jump on board and the NEW standard will become THE standard. The CYCLE will continue….see what I did there ba dum ching!!

  22. I’m just about to start a build so this has come at the right time for me. Was going to go XX1 Eagle but I will wait a couple of weeks for the XX1 DUB.
    It looks good too!

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