1

I'm looking to build an NS Decade dirt jump bike. I'm super confused about purchasing the right bottom bracket and crankset.

The frame specs says 73mm threaded.

Ideally, I'd like to use 30mm Raceface cranks (because they're cheaper than BMX cranks it seems like).

Which one of these should I pick? Does any of these options work for this frame?

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Also,

Would that work this these cranks?

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It seems to suggest that I should buy this for 73mm shell?

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A 'threaded' bottom bracket shell on modern frames means an ISO standard threaded shell aka 'BSA' or 'English'. Standard shell widths are 68mm, 73mm, 83mm or 100mm.

External threaded bottom brackets are usually used with 24mm diameter crank axles (Shimano Hollowtech or SRAM GXP), but 30mm axle cranks do exist - as you know because you found 30mm axle bottom brackets.

The crank you referenced has a 24mm axle so it won't work with any of the bottom brackets in the first set, however you correctly identified the bottom bracket it does need to fit in a threaded 73mm shell (RF-2925).

If you want a 30mm axle you need to identify the equivalent 30mm crank, the documentation should point you to the correct bottom bracket which should be RF-2881.

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