I have a (threaded) SRAM DUB BB on my RocketMAX. Always used ‘normal’ BBs (HT2) before that but at the time I built the bike the only 165mm cranks I could easily get were DUB ones.

Didn’t have a problem installing but the cranks/BB have never spun freely – they feel stiff if cranking by hand in the workstand, etc. and if I spin them up and let go, they slow and stop pretty quickly – if I flick the cranks round backwards I get 1/2 a revolutions before they bind and stop. Freehub spins super freely so it’s not that.

Not a huge issue (I don’t think?) but must be wasting some of my precious energy somewhere along the way when riding.

As I’m not familiar with the DUB setup, where should I be looking to fix this issue?

Too tight on the ring that takes up the slack (it’s got a proper name but I can’t remember it 🙂 )?

My dub bbs haven’t ever spun really freely tbh – they have a lot of seals to try and protect the bearings. Tbh I don’t think dub bearings in a bsa threaded shell are a great idea – 28.99 cranks don’t leave room very bearings that can fit very big ball bearings in them.

All you can check is that the lockring on the non-driveside crank isn’t too tight – all it’s meant to do is take up the slack once you’ve tightened the main bolt to the relevant torque. The lockring shouldn’t be really tight – just enough to take out any side to side movement.

You need a Hambini BB 😂

Sram manufacturing tolerances.

Tbh I don’t think dub bearings in a bsa threaded shell are a great idea – 28.99 cranks don’t leave room very bearings that can fit very big ball bearings in them.

Or any space for a decent thickness of aluminium to stabilise the bearing cup in the frame from excessive flex.

Or have any ‘grace’ time when the bearings seize and the alu axle keeps turning and wearing against them.

These are all things I have learned from bitter experience.

My dub cranks on my hardtail are on the last DUB bb from my stock, and axle slop is stabilised by gratuitous amounts of threadlock as a filler.

Granted Im a fairly aggressive 92kg rider on a Ti hardtail, but a 5 month BB life over the last 15 months is unacceptable.

Back to Shimano for me when the next BB dies. At least when the bearings seize the axle won’t get trashed and write off the crank set.

I’m 3000 miles into a BSA DUB bb, it’s never spun as freely as HT2 (but better than the OPs sound) and the last time I removed the cranks to check the bearings they were still smooth. Fwiw I never had an issue with HT2 BBs when people were saying they didn’t last, but if I replace these cranks I’ll go back to HT2 because I prefer nipping up 2x5mm hex than hanging all my (scrawny) weight off a bar to try to get the DUBs torqued up.

Did you double check you have the right number of spacers on the BB cups ?

As said above, is the slack taking up wheel adjuster thing too tight ?

Spraying wd40 helped

Basically they run tight. Spin freely for a day. Then the bearings fall apart

SRAM BB/axle standards have always been a bit crap, really. GXP wasn’t great. DUB doesn’t seem any better (ironically, DUB stands for “Durable Unified Bottom Bracket” apparently).

Scienceofficer

28.99 cranks don’t leave room very bearings that can fit very big ball bearings in them.

Or any space for a decent thickness of aluminium to stabilise the bearing cup in the frame from excessive flex.

But 30mm ones seem to work just fine. SRAM have just done a bad job of their BB design, again.

I can manage about 600 miles from a threaded sram dub bb. It’s just gone again so going to try an Uberbike one this time.

I’ve got a wheels manufacturing one to try when I get a chance to fit it but it was pricey and needs an also pricey tool to fit the bloody thing.

I have a Nukeproof bb ready to try. My last DUB lasted about 6 months of mainly local riding. I was wondering about drilling a hole in my bb to stop water flooding the bearings. I was also thinking about trying a Hope if nukeproof is no good as they work OK converted to GXP and outlast anything else I have tried.

Nukeproof DUB bb has lasted much longer than the standard Sram one for me.

A mate had a Nukeproof one on his Banshee Rune V3. It was shite. Now has a Hope one and it’s lasting much, much longer.