Sram Dub bottom brackets. God help me!

Having fun and games with my new SRAM Dub crankset at the moment.

Disassembled one last week to swap the crank. Had to apply an unbelievable amount of force just to undo the bolt. Local mechanic had already failed with a pneumatic impact driver…

Putting it back together today, tightened the bolt up and hear cracking sounds, and find that the little cup that sits between axle and bearing on the drive side has disintegrated. Perhaps it got dislodged when I put the NDS crank on and popped the axle through.

Is this repairable with a replacement cup, or is it new bottom bracket time?

Must admit that after years of having zero issues fitting and removing Shimano bottom brackets and cranks, this is all coming as a bit of an unpleasant surprise…

I’d check you haven’t got the spacers on the BB. Fully tight it should still have some preload movement in it, that is taken up by the adjuster on the NDS. I would remove the BB and check for 2 aluminium collars on either side. You could be pushing out to 78mm.

Did you undo the correct bolt on the crankset? If it’s similar to previous Sram cranks, the outer bolt is not meant to be removed. You’re supposed to put a 5mm (I think) allen through the hole and undo the inner bolt.

Definitely got the right bolt, was just a bit seized. The cup issue was a bit of a mystery, I reckon I must have slightly dislodged it with the axle on the way through, and it then cracked when I tightened the bolt back on.

Still, a fair bit of it was intact, so I just took off the sharp edges, shoved it back in, and carried on. Worked fine today. 🙂

I plan to stealthily covert the whole lot over to new Shimano XT/XTR as I go along, so if it eats itself I will take that as a sign from God that he wants me to spend some money.