Help! Swapping Sram DUB BB with Nukeproof DUB BB

Hiya – I’m probably doing something daft here so I’m hoping that someone can help me out.

I’m replacing a DUB bottom bracket on my Specialized Stumpy Evo 22. It comes with a Sram DUB BB and no internal spacers fitted and the 4.5mm external spacer over the crank arm on the drive side. It’s all Sram GX type setup.

When I come to tighten up the 8mm bolt on the drive side crank arm it goes fine until it gets tight and then the cranks stop spinning. I haven’t got close to the recommended 54 Nm yet because there doesn’t seem any point.

I’m using the Nukeproof 4.5mm spacer not the Sram one because the Sram one has a groove to fit into the Sram BB which the NP doesn’t have have and I’m pretty sure that I’m following all of these instructions.

https://media.chainreactioncycles.com/is/content/ChainReactionCycles/Catalogue/images/2020/November/Dave/How%20to%20Fit%20Nukeproof%20DUB%20Bottom%20Bracket.pdf

Am I going mad?

Are there some obvious daft mistakes I could be making?

Any help would be great.

Thanks!

have you completely wound in the preload adjuster on the NDS crankarm?

Thanks – good question. I did wind it in before I put it back in the bike but it didn’t seem to reach a stopping point. Is that usual?

I’ve replaced plenty of shimano style BB’s and cranks etc but this is my first Sram DUB attempt so questions like that are likely to be where I messed up.

Okay… well reinstalled the Sram one to make sure that I was not going totally crazy and it all works fine albeit with slightly worn bearings.

No idea whats up with the NP version but thought I would post this in case anyone else experiences this too.