Are the older 30mm spindle quarq branded carbon crank arms forward compatible with Dzero/Dfour DUB spiders? I know they are both SRAM 8-bold standard but other forum posts have left me unclear on the answer.
My Dfour finally kicked the bucket after 6 years of use when my chain dropped and got bent up in the frame causing the strain gauge to break. I want to know if it is possible to keep my crank arms and BB while just replacing the spider and chainrings.
Just depends on bolt number…I have an older SRAM BB30 crankset that is 3 bolt which were used with the Riken/Elsa PMs. My Dzero and DUB are 8 bolt.
Just note that if you have the older style sram carbon cranks with 8 bolts that doesn’t have a perfectly circular edge close to the spindle (shape like the Force 22 crank), it will not fit on all power meter spiders (like the AXS ones). The newer carbon cranks are more circular and narrower in the back than the old rectangular shape.
Based on these photos (Quarq DZero Power Meter Spider Review - FeedTheHabit.com), the Dzero spider can fit both the old and new shape cranks with 8 bolts
AFAIK the 8-bolt units are all compatible. SRAM e. g. makes cheaper carbon MTB cranks with a 3-bolt design — incompatible with power meters. That’s obviously a duck move. But the 8-bolt pattern units should all be identical. You just then have to pick the Quarq unit that is compatible with your preferred chainrings.
The good news is that Power2Max and Sigeyi both make meters which fit the older style SRAM interface for both road and mountain bikes.
Yes, I have in one of my bikes DZero spider with old 8-bolt Quarq 30 mm cranks without any problem.