The new SRAM DUB crankset platform launched in early January, it promised to bring their lightest mountain bike cranksets to date, and the end of figuring out which crankset will fit which frame and BB. The design uses a 28.99mm spindle for all BB variants, and they’ll offer the common BB standards to fit around it. This means no matter your frame, you simply get the correct BB and these cranks will fit. No more worrying about BB30, BB386, GXP, etc. But, really, they could have stopped at “lightest” and we’d still have been hooked…
Our test set just arrived, and as tempted as I was to request the even lighter XX1 Eagle DUB set, we’ve already put XX1 Eagle and GX Eagle to the test, so it was time for the middle child XO1 to get its chance. Our group arrived with 175mm arms and a 32-tooth X-Sync chainring installed.
The claimed 28.99mm spindle gives them an extra 0.5mm per side. That doesn’t sound like a lot, but think about the PF86 BB and how small those bearings need to be to fit a 30mm spindle inside them. Smaller balls mean they’re spinning way faster, the races are much narrower, and the whole system is way more prone to damage from minor contamination.
So, the seemingly marginal gains from 0.5mm larger bearings don’t seem to marginal when you do the math. Using BBinfinite’s PF86-to-30 6706 bearing size of 2.0mm as an example, adding 0.5mm to the diameter is a 25% improvement.
Is that why SRAM did it? And did they do that here? Or are they just trying to block aftermarket stuff for a while. We’ll ask them in person at Sea Otter. For now, this will be going into our next project bike, an XC race hardtail, which we’ll be documenting soon. Stay tuned. Now, back to DUB.
SRAM will offer four DUB bottom bracket options: BB30, PFBB30, BSA and PFBB (tested).
SRAM DUB ACTUAL WEIGHTS
On our scale, the individual parts weigh in at:
- driveside crank w/ 32-tooth chainring: 249g
- non-drive crank arm w/ spindle: 232g
- PFBB bottom bracket: 68g
- XO1 Eagle 10-50 cassette: 354g
- XO1 Eagle shifter: 125g
- XO1 Eagle rear derailleur: 280g
- Eagle 12-speed chain: 264g
Altogether now, the crankset with BB weighs in at 550g, which is 53g heavier than the XX1 Eagle DUB with BB we had on the scale in our launch coverage. Total system weight with parts shown here is 1,573g. For comparison, the original XX1 Eagle with BB30 spindle/PFBB came in at 1,565 for the same parts. A visual comparison of the new XO1 Eagle DUB cranks and the original XX1 Eagle cranks reveal no exterior differences in shape, suggesting the additional weight savings is coming from layup and internal parts…and the new spindle.
The takeaway? The XO1 group is now basically as light as XX1 was. Hooray for trickle down!
Watch for these parts on our Project XC Race Bike starting next week, which will be heading to the True Grit Epic on March 10 for a real test.